At first I put this down to upgrading to XF1.5 and it recounting their posts, with various soft deletes etc over time being now recounted.
But in the last few days the count has dropped another 14 posts.
The user in question doesn't have delete post or mod permissions.
I've checked my moderator and admin logs and cannot see any action by other members with that level of access recently.
Probably something simple, what am I missing?