Hi @don davis ,
Probably, it would be related to your account sync settings.
You could test to disable "Remember my preferences". If it stops changing fonts, you could clear stored settings and then sync them again.
How to stop backing up items
To stop backing up your settings and remove them from the cloud, turn off Windows backup settings on all the devices connected to your Microsoft account. Once this is done, you'll need to remove these settings from your account. Here's how:
Go to account.microsoft.com/devices
At the bottom of the page, select Clear stored settings