[zhoraster]

http://tinyurl.com/y72xwwqo

The 2♥ bid is (correctly) explained as 17- HCP, exactly 5 hearts and exactly 4 spades (with 6+ spades and 4 hearts I would continue bidding spades, with 5-5 or better, the first bid would be 2♦). Even with 6 spades, 2♥ is often better, as spades could be promoted by ruffing in dummy.

So why the robot "corrects" to 2♠?

Post mortem, 2♠ is pretty hopeless (though can be won on open cards); in 2♥, there are 8 easy tricks (9 with some defence).

[johnu]

If you read earlier topics in the GIB forum, you'll see that GIB failing to make the straightforward preference bid is a common problem in a comprehensive set of varying auctions. This has been an ongoing problem in the years that I have used GIB, and presumably back to inception of GIB 20+ years ago. My assumption is if it was easy to fix, they would have fixed it years (or decades) ago. I have no expectation this bug will be fixed in the foreseeable future.

[pescetom]

Horrific.
Would GIB have done any better if South bid Michaels (whether or not it allows 5-4)?

[smerriman]

The bids don't show exactly 5 hearts and 4 spades - that appears to be a recently introduced bug in the descriptions - should be 5+ and 4+, since there are many 5-5 hands that you wouldn't want to use Michaels on.

But yeah, 2♠ is crazy.