Could you please give some specifications of the system you are having the issue on? Like OS version (Windows 7 SP1 x86) browser version from the about page, etc. Also does the issue occur on other browsers with Chromium engine? Does it occur on Internet Explorer/Edge?
I've had a very weird experience on Windows 7 (both x86 and x64) not displaying Georgian unicode font first in Google Chrome, later on Opera. The letters were displayed as empty square boxes. The problem appeared after Chrome (and later Opera) updated automatically to the latest version.
The reason was a font! I did not try to pinpoint which one was responsible, I just copied all Segoe fonts from a Windows 10 system to the affected system and the issue was resolved. This fixed the small text displayed in the system tooltips (like mouse over the clock to see the date).
I am not sure it is related to your problem, but it is worth a try.