
Every operating system upgrade can change the fonts.
GET CALIBRE TO CORRECTLY SORT AUTHOR INSTALL
Now, you have no idea because every application install and uninstall can change the fonts. So that you would KNOW where every particular font comes from. I wish that Scribus would control ALL THE FONTS separately that can be used in a book. TrueType fonts, like Calibre, are giving the problems. The fonts that DO work, are OpenFormat -fonts and PostScript fonts. Not sure whether this is my end conclusion, but this is how it seems after initial testing. So, the solution appears to be to change the font AND not use Calibre and.
GET CALIBRE TO CORRECTLY SORT AUTHOR PDF
Having said that - if I read now the exported PDF (from Scribus) into Amazon e-book directly - against the recommendation and warning about PDFs not possibly working - none of the problems are present that I laid out for Calibre. I think all of that is wrong - possibly it could be made right by conversion options. because they are the paperback page number locations. However, this Calibre conversion messes up picture text location, creates a mysterious cover page from the first PDF page as an image and adds page numbers, which do not follow the flow of the e-book. Now the text itself comes out right into Calibre and conversion to EPUB as well. The latest advice - changing the font - did work out. but I need to double-check the logic in this. Is it really possible that some font can be so screwed up? It is strange that the other document has "tt" problems and the other "ff" problems - that kind of leads to think that it is not a font problem. install the very latest Calibre (and not used Ubuntu Studio default, which is a rather new version and the latest LTS, 20.04.x)
:max_bytes(150000):strip_icc()/003_convert-pdf-to-epub-4581324-8d372a67677d4c19aaa59a6c3db8d726.jpg)
I couldn't get any other way, there are many options in Calibre, to work either. I still tried that in Calibre and as you state, by default it should work anyway, if that is the problem. "tt" and "ti" is not about ligeratures - or so they say.

Putting that aside, this was test material only and thus not really relevant. I did try what you suggested, among something else in Calibre and that didn't do anything. I tried with an other test material and could find that problem there. It is not about "ff", "fi" and that sort of things. One of them was OK for Amazon Paperback, no problems. However, unfortunately, the answer is no joy in both ways.
