Strange signs like squares with question marks appear on some web pages

Appears to be a Font issue with the default Roboto font used by Chrome and Brave. There are 2 things I can suggest to do by opening the Font Book application in the Applications Folder. Restart computer after each one and test to see if the issue has been resolved. You will want to close the Chrome and Brave browser first:

Resolve Duplicates

• Open Font Book
• Choose All Fonts in Sidebar
• Choose File > Resolve Duplicates...
• Choose Resolve Automatically

Validate Fonts

• Open Font Book
• Choose All Fonts in Sidebar
• Select any Font in that Window
• Choose Edit > Select All
• Choose File > Validate Selection

Any errors in the fonts will be detailed in that window. If you see the Roboto font, users have found success in deleting it.

• Remove any Content Blockers or Extensions installed on Chrome.
• If that does not resolve the problem, reset Chrome to Factory Settings.
• Since the page loads correctly using Safari, you may need to check with Google Support if those steps do not resolve the issue.