Hm...but why is it happening on my system? A config-problem? I guest it's not possible to create such a behaviour on purpose (creating items in AH with lower buy-prices than bid-prices, because this would not make any sense...)
Could it be some DB-Issues? Some missed DB-Updates? (Autoupdates are activated in Trinitycore)
Edit: OK, I take it all back! I had a typo in my config:
"AuctionHouseBot.BidPrice.Max = 0.9" was "02.9"
I've corrected it and now the AHbot is working like it should :)