[Thranduil]

Deal: https://tinyurl.com/2ysh9vge

The jump to 6NT did not just happen here, it happened on most tables. It's completely brainless to jump to 6NT here. N/S may have a heart fit as 2♣ does not deny a three-card support, and there is a real chance that they do not have enough for the small slam (which actually is the case here, as everyone went down 2 or more times; for some reason the robot on W did not lead spades on my table despite me doubling the 2♣ bid) or actually have a grand - a jump to 6NT leaves no room to investigate.

[smerriman]

Surely it's the human in North who had blown a fuse? Jumping to 3NT with that hand seems awful to me. To be honest I'm not even sure what it would mean; a quick search on BridgeWinners suggests a balanced 16-17 count, and certainly denying a fit in both hearts and diamonds. Whatever the definition says, it's certainly not a minimum balanced hand; nobody plays fast arrival to 3NT.

[Thranduil]

Corrected the link, for some reason it pointed to someone else instead of my table. At my table and quite a few others the north player bid a reasonable 2♣ and the bot then immediately went off to slam.

[smerriman]

Well, this time it's you who blew a fuse, doubling when the opponents are in a game forcing auction just with four spades.. that bid would get severely punished against humans, but I guess you did it solely to trick the bot, which is fair enough. Doubles mess up many of their auctions, since here they can no longer bid diamonds naturally, and double is an impossible HCP to the bot, so it's simulating hands with 4 spades and 4 diamonds but any number of points. 6NT is a rare outcome of simulations; it will bid 2NT most of the time.

[Thranduil]

Yeah, the double in my place was questionable; but the bot jumped to 6 on most other tables too, even without the double and in slightly different auctions (sometimes S bid NT first, which ended up being worse because of the spade lead). In fact, 6NT-2 was only worth about 30% for us.

But it was always the bot jumping straight to slam from second or third level, no blackwood or other means of investigating first.