New build issue

I am having an in ground pool installed. concrete decks were supposed to be poured today, but plaster guys show up instead and start plastering pool. apparently plaster guys went to wrong project and were instructed to stop work and then left site. GC comes and has cement finishers start removing partially dry plaster from pool and into five gallon buckets which are then poured into deck rebar where concrete is supposed to be. GC states this is fine and is actually stronger than concrete, but concrete will be placed on top when truck gets here. How worried should I be?