I've found a bug in the hosting section:

After I was granted access to a server owned by someone else, I see this server as if it was mine's. Everything nice so far. I can edit all settings but when I save the settings on the "Access control" page (even if nothing was changed), my name gets removed from the authorised web-admins list and I lose access immediately. Other admin names (if present) remain unchanged.

I was able to reproduce this issue a couple of times with another team member, Ad-hoc servers are also affected.