Found out that text-size-adjust is causing this. I believe this was done to overcome iOS issue with unexpected font size increase, but on Android it does exactly the opposite by triggering it. This line is not needed at all, because this bug is already fixed with the meta tag:
Would it be possible to remove this rule entirely and still have disabled font boosting on iOS? Removing that rule seems to fix the issue for me, if it's not causing problems on iOS it should be safe to remove it. Also, meta tag needs a tiny update: https://bitsofco.de/ios-safari-and-shrink-to-fit/
Got a better idea what's causing this. I have a global setting for font size, if I change it to anything higher than default, text on Xf2 changes in size, but not everywhere and sometimes it changes its size back (for example in Account popup). I don't know if this is a standard setting on Android, but if it is, this should be fairly easy to reproduce.