This sounds like a character encoding problem, rather than a font problem.
Try adding a line like
wrapper.java.additional.X=-Dfile.encoding=UTF8 to the
ignition.conf file located in
/Program Files/Inductive Automation/Ignition/data/ - you’ll need to open as an administrator to modify the file, and replace the ‘X’ in the parameter with a valid, sequential integer in the sequence of parameters - somewhere at the end of the block that looks like this:
# Java Additional Parameters
Once you’ve made changes, restart the system.
Java defaults to the operating system’s default charset/encoding - on (English) Windows, that’s ISO-8859-1, not UTF-8. Generally we try to force all of our operations to just use UTF-8 anyways, but especially with a somewhat older version like 7.9.9 there might be some operation that’s not properly forced to UTF-8.