BuddyPress.org

If you hav so much session, i would be preferably for yu to have a local install where you can test and replicate what’s going on live site.

Now, regarding your avatar issue, it can be related to the same symptom reported here:
https://buddypress.org/support/topic/profile-pic-upload-failure/

or not !

In this case (and also the missing sidebar), we nead more details about your config, (ms, single), active theme and used plugins. Or at least a site URL.