Per Nick Underhill: Dennis Allen spoke extensively about the red zone issues. Says it’s a combination of play calls, execution and coaching

Yes, it's PC's fault.

One, we don't know what the audible actually was. Two, even if an audible was called at the line to change a hot route or something, PC still called the same formation four straight plays into the heart of a defense that had already adjusted after 1st down.

The concepts on those plays were dumb and predictable. Communication issues are on the offensive coordinator. The buck stops with him.
That's just not altogether true. 1st down 4wide 3x1 AK to the left. 2nd down still the same, 3rd down 3wide 2x1 in a much tighter set with TH in the slot
4th back to the 4 wide spread. Had to keep AK in for blocking since our OL was in shambles. In a hurry up in obvious passing downs there's not a lot change in formations. So on 1st down where Olave is not paying attention to DC calling the play and being clueless about the route this being his 2nd yr in the O. I guess that's PC's fault too.
DC missing a wide open TH on 1st down when he was looking right at him , also PC's fault. Shaheed being clueless as to which route to run on 3rd down? Of course It's PC's mistake.. Also in 2 of those last plays DC changes the call