I can edit or delete comments from other users. Do not care?
I just accidentally realized that in some conversations access to edit and delete other users' posts is enabled!!! and indeed, it seems to work!!!
Accepted answer
Hi. I reached out to the user and investigated this. It seems somehow this user got moderator rights for the "Solid Works Help" group only. Group moderators has some extra permissions for the group messages, as this user witnessed.
We removed user's moderator role and will investigate why it happened. We did not find any problems with the system or other users. Thank you again for your cooperation!