Could be both.I think the client is taking data from the cache not the server
I tried cleaning the client cache but it didn't work. I did not find any errors with the display of icons in the console. Also I noticed that not always shows the avatar after uploading it to the server. Need to uploading several times for it to appear.Could be both.
Either the client had tried to load the icons, but failed and cached the fail.
Or it has just issues displaying the icon.
Are there any file transfer requests when joining the server?
As well you've tried to clean the cache?
(Esiest doable via dev tools )
No not related in any way.