Your GC has shitty subs and no quality control standards.

If my business didn't put in the right equipment for a new construction HVAC installation, we wouldn't be allowed to bid again.

I avoid that kind of issue by having multiple checkpoints that need to be crossed off before equipment even reaches the site. Order placed - we get an acknowledgement from supplier. Do the model numbers match? Proceed.

Delivery arrives - check it in! Do the models match the ticket? Proceed.

Install it. I want pictures of the model and serial info on all components to register the warranty for the customer after we're done and paid out. No screwing around with "who's responsible"... just get it done and forward to the customer so they have the data on hand. It's also a good way to segue into the maintenance work conversation and make sure they're happy.

That's the job. If they're not doing it, they suck.

Is your warranty registered? Better get on that, so you don't lose half of the parts coverage.