We know that 2♣ is not game forcing over 1♦ in GIB's system. If 3♦ is passable, its description should include something like "11-12 total points", instead of "11+ HCP".
The 2NT description also has the same 5-card major bizarreness that has been mentioned before. The 2NT bidder cannot have 5 hearts or spades (or, clubs, for that matter).