North-South were good players.
West an ethical young pro, East a complexity-keen client.
We were playing RealBridge in face-to-face mode.
1♣ was strange. I guess East planned to show a weak notrump.
West's 2♥ systemically showed 5♥s & 5♣s. East alerted it but no questions were asked during the auction.
On lead, North asked about the auction.
East expressed some uncertainty. "2♥ is natural and forcing, I think."
West corrected by saying "I have shown 5♥s & 5♣s."
North woodenly led the ♠J-Q-A. South woodenly returned the ♠7 for -690.
After claiming 12 tricks declarer volunteered "I saw the double as 1♦. Over that, 2♥ would show 6+♠s."
Documentation was not available but there is no reason to disbelieve West.
The reason for bidding 2♥ seems irrelevant anyway. West eventually gave the right explanation.
While his partner's explanation conveyed UI and may have woken him up, his 3NT bid was not based on that.
16A refers to bids and plays, not explanations.
North new something was awry. Both opponents had denied four spades, which would place partner with five of them.
Yet partner did not overcall.
South might imagine that declarer had
♠Kxx ♥QJ9xx ♦- ♣KJxxx
Even so, South might cash the ♣A and switch back if partner discouraged.
Also, if West has that, North might have bid 2♠ over 2♥.
Do North-South have any recourse?