Project avatar file disappears after being forked

Summary

Avatar which previously existed is not presented at the project page.

Steps to reproduce

Create a project. Upload avatar image. Fork project.

Expected behavior

Uploaded project avatar should be shown on original project.

Actual behavior

Avatar is not shown (404 error on the image). Can take a while to show due to browser caching.

Relevant logs and/or screenshots

A couple of days ago I've noticed that the avatar is missing at https://gitlab.com/gitlab-org/omnibus-gitlab .

I uploaded a new one and I've confirmed that it persisted. This is also confirmed by screenshot that @rspeicher made:

https://gitlab.slack.com/files/rspeicher/F3K2TRVMG/pasted_image_at_2016_12_27_10_18_am.png

Earlier today (before the 8.15.2 deploy) I noticed that the avatar is missing.

Output of checks

This bug happens on GitLab.com