Hi,
For some reason, when an issue in my Jira server instance is 'unassigned', instead of displaying the regular avatar of the unassigned 'user' it shows this :

What I've noticed so far is that the request for the avatar is missing its ID in parameters, that's probably why it's not finding it (404) :

Any idea why that might be? We were importing some avatars from and old instance into ours when setting it up, so the files / records in 'avatar' table were definitely modified, but I'm not sure how to narrow down the cause of (only) this particular avatar missing.
Jira Server version 7.6.2.