Lensman

That may be best since my specific font issue has been resolved.  Also, a new thread with a more succinct title (about exporting and TTFs) would help others find the particular issue you are having.
I hope you find a quick solution.

You should check out what is currently happening on Adobe's feature request site:
https://adobe-video.uservoice.com/forums/911233-premiere-pro/suggestions/36257581-yes-please-support-linux-this-would-be-a-huge-m
As of this post, they have 10,822 votes to create a Linux version. 
The next highest voted feature request on that form only has 1,366 (that's down by a factor of x8).  The majority of the other request have less than 300 votes.
(I follow that thread closely, and they see an average of about 200-300 additional votes for this request every month).*   The overwhelming majority of those votes (over 10,000) have come in since this last December (2018). I know the sticker price for Serif going through the Linux port has gone up, but bare with me on this:
At one point at the beginning of this thread a moderator mentioned that Serif would only consider a Linux port if they could reasonably guarantee that they would make back the roughly $500,000 it would cost them to do. Well, as Adobe's site proves there are at least 10,822 people who are clamoring for some kind of professional design software option on Linux (a void Adobe is still unwilling to fill):
10,822 x $50 = $541,000
Allowing that the number of people who actually have voted on that thread merely represents a marginal snap shot of the demand out there, I think it may be well with in Serif's interest to look at this with some seriousness.
The free /open source image processing solutions available on Linux are closing the gap at a fairly steady pace (all of these options are available on Windows, and Mac as well) but they do still have a little ways to go (as a person who has made a living with design software for over 15 years, I think I am qualified to say that they do not have as far to go as you might think).  Affinity and Adobe, I believe, would be wise to try to overshadow the void these free solutions are threatening to someday fill, sooner, rather than later.
 
* This particular feature request thread on Adobe's site is specifically for Premiere Pro (Adobe's non linear video editor), however, if you read through any single page on the thread, you'll quickly realize that what they are really asking for is support for the entire Adobe suite (Ironically, there already is a professional non linear editing package available for Linux - a solution that strongly competes with the capabilities of Premiere Pro: Blackmagic Design's Davinci Resolve). If you read through any page on the Adobe thread, you'll also see the common refrain that we Linux fan's are so familiar with - the only reason that these people are still using Mac or Windows is because Adobe is not supported on Linux (Serif, if you do any digging around the internet, you'll find this sentiment echoed over and over again). 
Serif, your software can sooooo compete with Adobe's.  Don't you want to try to steal an untapped market from underneath them?

Just want to add a voice to those calling for Linux versions of the Affinity Suite.
I can drag out the old tale of how I am disillusioned with Apple, or how Windows is not Unix enough for me.
I can drag that out, and it would be true, but the real thing for me is that with the presence of very useable (even pleasant!) distros like Mint and PopOS, and with the range of software now available for these distros Linux is a real desktop alternative. The one thing that is missing is a good graphics package. GIMP does not cut it and neither does Inkscape.
If Serif was present in this space they would be alone, and they would be singlehandedly making the platform a more viable choice for technically-inclined graphic designers such as myself. Kid yourself not, there are a lot of us. The beauty of PopOS combined with access to a proper suite of graphics tools could push many of us over the edge.
There are two things I like in my computer world right now, PopOS and the Affinity Suite.
I cannot and will not attempt to instruct Serif on the economics of the thing, but one way or another I am migrating to PopOS out of despair of my other options and Apple's once-fabulous hardware.
I am begging Serif to come with me, and I can't be alone.

make a version for linux?

Try this ... TradChineseSealScript.ttf
I do not have any experience with CJK fonts, but it seems to work.
Did some quick tests in LibreOffice, listed properly in fonts list, inserted some characters,
and Export to PDF worked properly.
Give it a try in APub and let us know how it works.
 

Thank you for the replies.
I am on a PC.  It is a Chinese font.  It is not outlined.  I use it right next to other fonts on the same page in the same manner.
The file is called "HDZB_25.ttf", but in the list it is called "汉鼎繁印".  I use it with several other Chinse fonts that work fine in Publisher, Word and InDesign.
Upon further investigation, I found that the file embeddability is Restricted (in the properties panel)... If that is the reason, then why does it work fine in Word and InDesign, but not Publisher?