It is not SME bug and rather request to forum administrators.
It looks like current auto session timeouts are too short and many people logged out before they finish posting long messages. Can it be increased to some sensible time (15 Min)?
Also on the same note, the new defaults with automatic "Notify me when a reply is posted" checked is a bit annoying. It was better then default notification was not selected and ONLY topics you select will notify you.
Thanks.