This sounds more like a flaky order matching algorithm than anything -- bids over asks should be executed at the ask (or the other way round if the ask comes in later). I.e. it should never happen on an exchange.
Yeah, could be, but it's interesting that it only happens when the price approaches $130.
remember bitstamp as auto trading built in....ppl may have orderbooks open at stated price
and that's another possibility--I was thinking of auto trading bots, but it seems like if they were programmed right, they wouldn't bid $10 over ask -- that was a 50 btc order so the overbid cost $500 for nothing.
Trading has been normal while the price was around $135 with bids below asks.
Price is approaching $130 again, so it will be interesting to see what happens and if we start seeing bids over ask again in what looks like an attempt to keep the price over $130.