[Siegmund]

Link to hand

I don't much care for GIB thinking that a 6-2-3-2 1-count is a penalty double after its partner shows a minor 2-suiter, and I don't much care for it selecting a spade lead against 5Hx either.

Looking at the explanations, the root of the problem appears to be its inability to believe that sometimes partner is bidding on distribution, or not bidding to make at all: it took my 2NT-followed-by-5D as "29-30 points"?!

The same hand caught half the field in a robot tourney today on similar auctions.

I really should have learned from this accident, but no, half an hour later it did the same thing to me after the other side had a strong Michaels auction:

Second hand

In both these auctions, humans grasp the idea that the side that makes the strong cuebid is bidding on strength / to make, and the side that just bids suits is bidding on shape / to sacrifice, and even have forcing-pass rules accordingly. I don't expect the bot to know that much but I do think it badly misevaluates its defensive prospects when partner makes a shape bid.