I was using hte latest beta today to see how it was coming along and its looking very nice. K the problem i had was after a full scan, i then tried the buyout options on the additional tab. I didnt see anything worth following up and went back to the normal AH tab to scan for some runecloth. Auctioneer attempted to buyout every piece in the AH! Anyway as i was using a nube toon he did not have much gold on him thank god else i would have been well out of pocket Anyway likei said if you do a buyout scan,then do a normal scan it atttempts to buyout something
I saw something like this happen to me a couple of times today for the first time. I haven't been able to deduce the exact cause of the problem though. What I suspect you saw was not an attempt to buyout all the runecloth, but an attempt to buyout the same stack of runecloth over and over again. At least that's what happened to me. The chat window filled with messages about removing the auction signature.
I did fix one problem related to this though. Once a bid/buyout fails on an item, it should be skipped. This should prevent getting stuck on buying out the same item over and over again. This will appear in 3.3.672 or higher.