How is the North hand worth a cheaper minor rebid only?
And then not worth continuing over 4♥?
Incidentally, putting this into a bidding table, GIB would bid the non-forcing 3♥ as South. North then uses Blackwood to reach 6♥.
Edit - as another bug, I'm not sure why 2♥ was described as a weak 2 bid! But that's not relevant, since a bidding table results in the same cheaper minor bid (with the correct description for 2♥).