andmocychmen

Oh! Hidden secret! Feels like the Da-Vinci Code. Thank you for the clue!

The file you attached is a PDF created from Affinity Designer and renamed as .AI. It did not have objects in "Layer" layers, but even if it did, it would not work.
Here is the same file after opening it in Designer and placed in "Layer" layers and exported so that "Layers" are included:
cream cheese garlic single die-cut_exported_as_pdf_w_ocg_layers.pdf
When you open it back in Designer, layers are shown (much like in the original .afdesign file, but only up to one level):

But this is what Illustrator sees (even if you rename the file as .AI):

This is what Adobe Acrobat Pro or a good PDF reader like PDF/X-Change sees:

...and this could be used by the print shop to print the file unless they really need to open it in Illustrator to do some preparations.
As was shown, Illustrator does not read in PDF layers but flattens them (see "1 Layer" status text in the Layers panel above). Illustrator only reads in native Illustrator layers (also when it itself saves OCG layers in its PDF export).
This is how CorelDRAW opens the file (PDF layers are opened as CorelDRAW layers):

...and when Corel exports this as an .AI file:
cream cheese garlic single die-cut_from_corel.ai
...this is what Illustrator sees (note "2 Layers" in the status bar text of Layers panel):

...but this is what Affinity Designer sees when it opens this file:

So, we have come a full circle demonstrating that Adobe Illustrator native layers are totally different from so called PDF layers (or "OCG layers"), and that native AI layers can be imported and exported only by a few apps other than Illustrator.
 

In Affinity Designer the concepts of objects, layers and groups are pretty confusing. What you have in that AI file is one layer with two objects.
If you want to export a PDF with two layers from Affinity Designer, you have to do something like this:

Unfortunately Illustrator will not read the layers from a PDF.

If the print shop does not really need to open the PDF in Illustrator, they could possibly do printing from a PDF that has the printable and non-printable parts separated as so called "PDF layers" (or OCG layers = optional content group). Affinity Publisher and Designer can export their native layers (layers that have "(Layer)" appended to the layer name), as PDF layers when creating a PDF (the option is by default selected when exporting using "PDF (for export)" preset), but can be checked separately from the "More" options page when exporting to PDF. 
But if the print shop really insists on having an .AI and separate layers for the image and vector, the only solution I know that really works, without needing to use Illustrator, is to place the image and vectors in separate Layer layers in Designer/Publisher, and exporting to PDF using the option that export Layers and then open that file in CorelDRAW or Xara and export to .AI. Just renaming a PDF to .AI does not work because Illustrator flattens all PDF layers: it only retains the hierarchy of native Illustrator layers. CorelDRAW and Xara retain hierarchy of PDF layers up to first level, and can then also export these layers in .AI format so that Illustrator reads them.
Xara for some reason converts a CMYK document to RGB but if that is not a problem, and the fact that this app is Windows only, this might be a kind of a solution (perpetual license around USD50). CorelDRAW is also available for macOS, and perpetual license is available, but the app is expensive both when purchasing a perpetual license, and when subscribed, so this is hardly an alternative to getting Illustrator.
That CorelDRAW can truly write and read .AI (to some extent at least) is probably based on some kind of agreement between Corel and Adobe to share their proprietary file formats (both importing and exporting). Xara is probably just hacking away what it can, and at times this may be helpful, but it is not always robust.
One possibility might also be placing the image and vectors in separate layers and export to SVG. This means that RGB only is supported, but the job could at least be opened in Illustrator as organized to two layer-kind of groups (not actual layers, though) so that the image and vectors are in separate containers from each other. But while this could be a technically valid solution, it of course is not the same as what was initially required by the print shop.
You might possibly resolve the problem also by changing the print shop to someone more flexible and pragmatically oriented one...

Alternatively, Photopea might be able to open your Affinity file and convert it to an AI file, which (if it works) might preserve more information.

Hmm you can try out (inspect and compare) what some PDF-to-AI online tools do create out of your PDFs as Ai files then instead ...
https://magicul.io/de/converter/pdf-to-ai https://pdfmall.com/pdf-to-ai ... etc.

Gosh okay, the thumbnail. I clicked like a maniac on the name and nothing happened.
Case closed.

Where did you double-click? I think it must be the adjustment layer thumbnail.

Use the Export Persona and go to the Layers panel, any layer there (artboards will show up as layers) can be made into a slice by using the button at the bottom of that panel.

@andmocychmenin addition don't forget to use a Document Palette and Global Colours.

You could use Symbols.
 

There should be an option in Preferences - untick "Show lines in points". 

Hi @andmocychmen,
I can confirm this is logged with our developers as unavailable currently on the iPad version, though unfortunately 'm not quite sure for the reason of this.
I'll be 'bumping' this report now with your post, and requesting for these options to be added once again. I hope this helps

Okay I figured it out.
I need to both:
apply the transparent background to the artboard changed document setup and tick transparent background in the color tab. Thanks!

Unless you saved it, using a unique name, we may never know. Once you selected a brush, if you modify it in any way, it is no longer the same brush, it's a new brush. All those brushes are presets, a starting point.
If you didn't save the brush, well the info probably is floating around somewhere just below the ozone, where the bovine emissions lurk..😄

Yes, but Artboards can set Fill Color individually.

 

In Publisher, alternatively to tables, you can also use text frames with a blank paragraph decoration. That's really easy peasy and much more precise:

Of course, you can then switch back to Designer. All text frame and paragraph attributes will remain intact, albeit not editable.

It is possible non-destructively without adding another object:

 
(Um… my wife's just told me she's hungry, so I have to cook dinner now. Let me know if you've found out how it works in the meantime. If not, I'll get back to you about in an hour or two, to tell you the whole secret… )

Oh, sorry, no. I did not notice that you were using AD.

As an alternative to @Joachim_L's suggestion, here's a really quick way of doing this:

Draw two rectangles: one with just the fill and one with just the outline. Convert the outline rectangle to curves. With the node tool, break the curve at the top left and top right node. This will separate the top line from the rest of the object. Select the top line and apply an individual stroke to it. There are downsides of this approach (e.g. after converting to curves, you'll lose rectangle properties for your outline object), but this is the easiest way I can think of to make this work.

As an arch user, I'd be more than happy to have a SteamOS like distro to run Affinity in, and that's probably a viable course of action because they'd have absolute control over the OS out of the box.

Also, for clarity, Affiniti themselves estimated that it'd be $500k to port it over. Not zero money, but, that's only around 10k licenses to break even at the current pricing. My assumption is that the current install base is much, much larger than 10,000 users. They could likely also hedge that a little by offering an enterprise support tier for bigger money.

The fact is, the only option on Linux being half-speed adobeCC is a piss poor one. Sure it comes cracked out of the box, but it is very slow. I've used it, it's terrible, and I have an AMD GPU, which normally works fine for steam/proton. What they're looking at is a smaller market, but one that would have zero options if it weren't for Affinity.

An alternative to the advice above, in Designer only, is to use the Point Transform Tool.
Select the tool and then drag the layer over to where the node is.
If you have the right snapping options set to ON then the dragged layer should snap to the node.
(See attached video which was recorded with the latest beta but it should work in the latest commercial release too.)
2020-09-17 14-06-30.mp4

Bug or no bug, something not being clearly defined in the documentation does not justify arbitrarily defining it as it might be defined in some other (in this instance totally unrelated) application area.
So what? While an object box can be cycled through more than one kind of selection box, it can have only one bounding box, which has exactly one mid point that is always in the same place in & defined by that object's geometry.
It means the two dimensional geometric space the object is defined in. It has nothing to do with the temporal dimension of an animated object because that dimension does not exist in the Affinity apps.
A snapping point in that 2D space may or may not be on the path of a curve. It could even be at some point far removed from any of the nodes of that curve or its path. The red & green snapping indicators make that clear even if the documentation does not.