Cannot change some text styles
Go to Style and select Text Styles (the bottom tab), then go to Hairpin and change the font, then press OK. It seems like something was changed, since the file name has an asterisk at the end. Then load Styles again. The font for Hairpin is still the custom one you selected, but go to Palm Mute (which is above Hairpin) and you can see that the font for that is changed too, even though you haven't touched it. Then go to Bend (which is below Hairpin) and all is normal. Then go to Hairpin again, and your change has been reverted.
In fact, nothing has actually been changed during the whole process. If you have a hairpin (such as a cresc. line, IIRC technically it's a hairpin even though it's really more of a text line) on your score, you can see that it's never been changed. This can be confirmed by looking into an
.mscx file, the change was never recorded, even though the change can still be seen from the UI the next time you load the file or even the program.
This is probably true for some other tabs as well, but I didn't check them one by one.