Yes, this is a bug.
In pop_moderate.asp, line 275, change this:ProcessSubscriptions MemberID, LoopCatID, LoopForumID, LoopTopicID
to this:ProcessSubscriptions LoopMemberID, LoopCatID, LoopForumID, LoopTopicID
It was sending the member id of the member that was currently logged in, which was the moderator, instead of the member who made the reply, to the Subscription function.
This needs to be moved to the bug forums.
- David