Adriandw

@Hangman, You're right.
In Designer, I have a complex image made up of text and vector curved shapes.
When I export it as an SVG from Designer, Designer decides that some of the image will be rasterised, specifically an ellipse with a radial gradient fill which is the subject of a layer mask.
 
 

@walt.farrell Thanks, you're right. It hadn't occurred to me to point to an existing anchor, but it works.
That's acceptable behaviour for a beta version.
But I'd hope that the production version would be smart enough to create a new anchor if necessary and to make use of an existing anchor where one existed, rather than create a second, duplicate anchor.

I had something similar when I couldn't edit the text in a frame.
Bypass was to close and reopen the file.
Haven't done enough work to figure out if it's repeatable and if so what sequence of events causes it.

In my experience with InDesign, and with a two column layout, if you add a new heading with span columns set, it automatically balances the text columns above that point.
Then the heading spans both columns and the text flow starts below that in the left hand column.
There may be other side effects of spanned columns, the point you raised would not be a concern for me.

@Chrysogonus - agreed.
Accessibility is now a legal requirement in the UK for public sector websites (even for very small public sector bodies who struggle to afford Adobe software).
This includes any PDFs on the websites.
Even MS Word now has an option to save an accessible PDF.
 

Please please please implement span columns. I've made the switch from InDesign, and this is killing me. My usual workflow is to import text, apply styles, and then start adding images and pull quotes to the pages from the beginning, trusting the layout to flow from page to page. I have a spanning title style that marks the start of new sections, but there are always story adjustments that cause changes in exactly how the text flows. Having to come back and move all the separate text frames that make up headings to align with section breaks is a nightmare.

@Chrysogonus - agreed.
Accessibility is now a legal requirement in the UK for public sector websites (even for very small public sector bodies who struggle to afford Adobe software).
This includes any PDFs on the websites.
Even MS Word now has an option to save an accessible PDF.
 

Agree, yes it should be a paragraph style, doesn't need to be linked with Baseline.
The InDesign implementation uses the paragraph settings panel and that works for me
 
 

@Clayton King
Even MS Word can do it.
I produce a regular magazine in Word. In preparation for an intended future progression to Publisher I switched the latest Word version to 2 columns.
In MS Word, if you do Insert/Section Break/Continuous it achieves the effect that I would like to see in Publisher (which previous posters have been calling Span Columns).
It starts a new left-hand column and balances the text in the columns above it, so that the new article/story fills the page from that point down, across multiple columns. 
Then if you add or remove content from before the section break, the columns above the break rebalance as necessary.
 
 

@walt.farrell I agree, it's great to see Serif coming out with so many incremental enhancements to Publisher.
I wasn't expecting IDML import so soon and that function will help me free myself from dependence on InDesign. 
I'm hopeful that it won't be too long before they implement column-spanning.
For me and others, it's worth occasionally emphasising the importance of column-spanning as input into Serif's prioritisation.
@Catshill On a short, single-page document, you're right, the lack of column spanning is easily worked around.
On a long document with two or more columns, it's common practice to use a full-width heading between sections/chapters.
As I go through iterations during the preparation of the document, I can't
because the size and also page break locations will change as the document develops.
If anyone has an easy workaround to that problem, I'd love to hear it.

Same problem - I don't think I have any frames with overflowing text but I get this message.
I'm using a 2-column text frame for the main text.
The problem seems to have started when I added an image frame, and a text frame for the caption (and set the text wrap options to Jump).

I produce publications for three non-profits - I’m using a copy of InDesign which I purchased as a component of CS6 several years ago - neither I nor the non-profits could justify the monthly charges for the latest InDesign. I’d love to switch them all to Affinity Publisher but without Span Columns (and cross-references for longer documents) it wouldn't be a complete solution and therefore I’ll hold off persuading them to adopt it (although I have purchased my own copy).

Congratulations to Affinity. I hadn't expected InDesign import so soon.
This is great. I've held off upgrading to macOS Catalina because my InDesign CS6 will stop working.
I've usually stored my InDesign projects as .indd files.
Now, as long as I go back and export the old .indd files to idml I'm free of the dependency on InDesign. 
The idml import isn't perfect, but I'm sure it will get better and it's a very good start for preserving access to old InDesign projects.
All I now want for Christmas is the span columns option for paragraphs.

Walt - thanks.
I hadn't yet found the leading override that was hidden away under Character/Positioning and Transform.
I think your theory is probably right: the special character has overridden the leading for the paragraph in such a way that you cannot make any more changes to paragraph leading.
But you can still increase (though not decrease) the leading using "Leading Override" under "Positioning and Transform".
 

I produce publications for three non-profits - I’m using a copy of InDesign which I purchased as a component of CS6 several years ago - neither I nor the non-profits could justify the monthly charges for the latest InDesign. I’d love to switch them all to Affinity Publisher but without Span Columns (and cross-references for longer documents) it wouldn't be a complete solution and therefore I’ll hold off persuading them to adopt it (although I have purchased my own copy).

While I don't think Span Columns and Split Columns missing from APub is as "crippling" as some users state, it is inconvenient enough for me that I can't justify investing the time and money to learn the app, to begin with.
I don't expect a full InDesign replacement on day 1, but Span and Split columns is a hell of a lot more important than the Stock photo integration.

Yes, I truly want to switch from ID to APub, but can't as long as there is no Span Columns. I do newspaper/magazine layout and it is a must have for that kind of work. I did buy it though, in hopes that Affinity will add this feature soon. 

Yes, span columns is definitely a must-have. I remember when this feature was introduced in InDesign and how very much easier it made life of a layouter.

Now I have had time to play with the final release of AP, I am very impressed with how good it is, but there are still two deal breakers in it that need fixing before I can recommend it to the various not for profit organisations I advise. The first is the one discussed here, which I posted about in June - spanning columns. This is not a luxury as some one has suggested, but a massive time saver and aid to good layout. (The second is tables not flowing onto other pages, an even worse oversight).
I am hopeful that both these will be in future releases as there is some evidence that Affinity do listen, as long as we make our cases strongly and professionally enough. For instance, I, along with many others, bemoaned the fact that the earlier Betas did not allow images and tables to flow with the text. We were told by a staff member this was not on the road map and unlikely to happen, but there it is in the final product (or something very like it, pinning)

@fde101, I'm with @whitewolf7070 and @captain_slocumon this one.
On a multi-page two-column layout where you have sections that might or might not span pages depending on subsequent content, none of the suggestions above is a practical workaround.
Ideally you'd be using a master layout with a two-column text frame,  with the frames linked from page to page.
But without the ability for a heading to span columns, you have to split the text frame at the point where you'd want a heading spanning columns. So you'd be forever tweaking the point of split as you add or rearrange content.
It's perfectly reasonable to discuss the relative priorities of features that we would like to see added to Publisher, but I haven't yet seen a workable alternative to span columns.
 

I'm loving AFPub but ...
Pinning should be a really great added function when I have a diagram or image that needs to stay with the associated text when I add or delete chunks of text above it.
But I don't think it will help with my span column problem. 
Last year I produced a 12 page two column leaflet using Adobe, with a 2-column master page layout.
On a major heading, I would set the span column option to All.
All the text up to that point would be reflowed across to balance columns above the heading.
Then the text following the heading would resume the two-column format below the heading. See image.
I wouldn't have to break text boxes or do anything tricky, and if I added or deleted chunks of text, I wouldn't have to resize text frames.
There doesn't seem to be a straightforward way to do this in AFPub yet, especially when using two-column master pages. 

+1 to that.
I'm on InDesign CS6 (the last version you could purchase), but it's a 32-bit app on the Mac so won't run under the newly announced Catalina Mac OS 10.15.
I've also pre-ordered Publisher, but I'll need to keep an external hard drive with Mojave to boot from and run InDesign CS6 when I need to span columns. 
I hope Publisher sells well enough to justify adding that feature. It would be good, once Publisher has shipped, if Affinity could share its roadmap of features it hoped to add in future release.

I'm loving AFPub but ...
Pinning should be a really great added function when I have a diagram or image that needs to stay with the associated text when I add or delete chunks of text above it.
But I don't think it will help with my span column problem. 
Last year I produced a 12 page two column leaflet using Adobe, with a 2-column master page layout.
On a major heading, I would set the span column option to All.
All the text up to that point would be reflowed across to balance columns above the heading.
Then the text following the heading would resume the two-column format below the heading. See image.
I wouldn't have to break text boxes or do anything tricky, and if I added or deleted chunks of text, I wouldn't have to resize text frames.
There doesn't seem to be a straightforward way to do this in AFPub yet, especially when using two-column master pages. 

Thanks for the suggestion and example Walt. It is a technique that seems to work in your example, but why have to create TWO text boxes and format them as well as the text itself? I don't see this as a regular substitute for the simple "Span Columns." Why don't the programers simply include it? Maybe there's a reason, but as a designer, it escapes me.

Thanks, that's great. I'm still adjusting to AF Publisher's dialogue structure and hadn't investigated the Studio>Fields settings.