I just noticed my reply wasn't related to what Pedro was originally saying. I answered it at 5am while I was getting ready for work so I apologize, being half awake and all.
Did anyone notice this before the "Remove Thanks" function was added? In this case I don't think it's people going back into old posts and using the "Remove Thanks" function. To lose 25 or so posts in less than a day would mean one person would have to remove them from 25 posts or 25 different people would have to remove them.
Won't really know a definitive answer until Alex has a chance to look into it.
Slick