There's a rather annoying behaviour with the Auction House in that when the item you have selected is being actively bid on, it will try to refresh the amount, and next valid bid amount while you are perhaps trying to up the bid above the minimum to deter further bids. I've been snagged by this bug-of-sorts twice, but fortunately on both occasions the items I was bidding on had a reasonable (if not a bit too high) buy price so the system capped out at the buy now price.
The other day I found a rather attractive Heavy Gear on a Short auction for 25cr and no bids. Quite a bargain so I bid on it. It got to Very short and then the inevitable "dang it!" set in as someone set out to poach my bargain shiny. I think at least two other people were having a go because I started getting too low warnings. The bidding got into the 60's, when all of the sudden: 65,100. (No buy-now price) Obviously the poor soul had wanted to up the bid to 100 and hadn't noticed the system update his bid before he typed what should have overwrote the old value.
Needless to say, someone auctioning a heavy gear would have gotten one hell of a surprise e-mail, and someone else is probably cursing and filing a bug report. I'd be curious to know whether Three Rings would refund the Crowns from such an obvious error due to glitchy bidding behaviour. (in which case I'd like another shot at that heavy gear!! :)
... and a warning.