Hello CSlavova, and welcome to the forum.
I have seen a few help tickets with a similar issue, which seems to be caused by the computer having a local installation of the Segoe UI fonts in addition to the systems-level copy installed by Windows.
Uninstalling the Segoe fonts from that local location should fix the issue you’re having. However, the process to do this is slightly more difficult with these Segoe fonts, perhaps because of that system font connection. That means, you will likely need to use the registry editor to delete those local copies of the font.
Before you do that, we strongly recommend copying the Segoe UI font files from C:\Windows\Fonts
to save a backup copy, in case uninstalling the fonts affects the system display and they need to be reinstalled globally. When another user encountered this issue, deleting the font files from the registry resulted in Scrivener looking fine, but other parts of the general Windows UI looked odd, and reinstalling Segoe corrected it.
Before you begin editing the registry, you may want to have your PC perform a system backup, just to be sure you have it saved if needed. (And, after all, regular backups are wise in any event.)
Once your backup is completed, please open the registry editor (depending on UAC settings, that may require an admin password) and then navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Fonts
In the righthand pane, please select the “Segoe” fonts (double-checking the path for the fonts), then right-click and choose Delete. Finally, navigate in File Explorer to C:/Users/currentuser/AppData/Local/Microsoft/Windows/Fonts/
and delete those same font files.
Here are the steps with annotated screenshots: https://www.tenforums.com/tutorials/127007-delete-uninstall-fonts-windows-10-a.html#option5
Then, please reboot and check the font display in Scrivener and Windows. Ideally everything will look correct in both, but if not, reinstall the Segoe fonts copied earlier (select the files and right-click to choose install). Please choose the option to Install for All Users, which will place them in the C:\Windows\Fonts
location; it will require an admin password, and it may mean replacing an existing file, so just click OK to that.
If you’d like, you could try the local option first; if it doesn’t work, or reinstates the Scrivener UI problem, please repeat the previous steps and then reinstall the font globally or download a fresh copy and install it.