Cannot create a group with an avatar set as the image, it hangs on submit

Hi,

When I try to make a group - if I select a image avatar during this creation process, I can never get past that screen to create the group. It just appears to hang (AJAX-y) until I cancel the request. When I remove the avatar and just submit without it, the group creates fine.

I can then upload an avatar _after_ the group has been created and it works fine (using the same image I tried to use during the group creation process).

Not sure what the issue is. I don't see any Javascript errors or other things, and it only occurs if there's a thumbnail. My temporary solution is going to be to remove the avatar field from group creation, but I'd like to know if there's an actual fix or if this is a known bug / something weird with my setup.