Something went very wrong with the descriptions here.
Firstly, Gib's 2♦ apparently denies 4 spades. The bid itself seems fine.
The main problem arises after Gib's 3♠. My 4♦ shows 17+ points. Yet there wasn't any alternative bid - the one I really wanted to make was a natural 4♠. Gib described that as.. a cuebid in spades.
Incidentally, somehow 5♦ by Gib then shows less points (12-13) than its previous bid (12-16).