This has happened to me a couple of times in the last week. Right now I've got a $49 item with zero bids on it, but AS thinks it has 21 bids and is prepared to bid $139 on my behalf. Ahh-- AS bugs-- ya gotta love 'em!
This is a new bug that I haven't seen before-- and it's the first time I've seen an AS bug that could cost me money. For example, I shudder to think of the situation where a couple of different AS users are bidding on a $10 item, but the software bug has determined that it's going to bid $100 or $1000 for both of them! Maybe you could get out of the sale somehow, but beware.
With the last one a few days ago, what worked for me was to delete the snipe, and then reload it from my watch list on ebay. I couldn't get it to load the correct price any other way, like by using 'Update Prices' or anything like that.