There is no such thing as a ‘general communication’ in NEC contracts. The project manager can only issue those instructions that the contract states they can. As long as the instructions are in accordance with the contract, you are required to obey them, see clause 27.3.
If there is an ambiguity or inconsistency, the project manager is required to issue an instruction resolving it. If the project manager’s instruction changes the works information, that will be a compensation event under clause 60.1(1), unless one of the exceptions in that clause applies.