I noticed certain circumstances where an explanation was given. For example, this happened on the recent Dez jersey that sold. Bids were deleted due to an error in the original listing which mentioned a specific game date and they later realized that they couldn't clearly identify the specific date the jersey was used and updated the listing. At that point they deleted the bids to give people a chance to get out of their bid given the new info about the jersey.

I do think there are also these phantom re-listings and double listings that aren't explained by the above.