Glad I'm not the only one having this problem. I thought I was going crazy  

I've only noticed this happening with one random generated user avatar (most users upload their own . 

As a quick fix I downloaded the generated avatar from their profile page and uploaded it as a custom avatar. 

You can use WordPress and Custom Uploaded avatars. The URL type of avatar is not fixed yet.

Thank you for fixing, all working properly now 🙂