This isn’t happening on Meta, but some other Discourse hosted sites are not showing letter icons for desktop views (in Firefox). They appear to work in the mobile view.
All of the users in this topic, found searching for something else:
Reviewing the code, it looks like {first_letter} and {color} get gsubed in in self.system_avatar_template in app/models/user.rb, but size seems special because it changes based on view (hence working for mobile). I’m not clear where size is supposed to be subbed in and is failing to be.
I clicked on the number to get that menu, but without a notification it is invisible and unclickable.
In browser console I see only one error, repeated three times:
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. ExtensionCommon.jsm:264
withLastError resource://gre/modules/ExtensionCommon.jsm:264:9
wrapPromise/< resource://gre/modules/ExtensionCommon.jsm:315:11
Given the location, the message is not Discourse related, and might or might not be related to the icon problem. I’ll guess I’ll give FF55 a try for this.
number to get that menu, but without a notification it is invisible and unclickable.