[uva72uva72]

My link

IMPs, ACBL robot individual

Two issues to raise:

1. North's hand does't look like a negative double to me. It's every bit of a 4♥ bid. North's failure to describe its hand accurately immediately leads to trouble later.

2. If South can have only 17 HCP for its 3NT bid, why does North go directly to 6NT? 4NT would seem the limit of the hand.

I'm also of the opinion that 3NT should not show anything more than an opening bid. What is South supposed to do with a minimum hand with fewer than 4♥ and a ♠ stopper but no desire to defend 3♠ doubled? But the real issues here are the misuse of the negative double and the assumption that South is at the top of its bid (the latter a persistent problem).