Under all options of the ECC. the Contractor is NOT required to submit their drawings etc to the Project Manager (not the client) at all unless it is specifically stated in the Works Information that he is to - see clause 21.2.
If the Works Information requires him, then it makes sense for him to submit it as part of standard form in order to reduce contract administration i.e. programs save time in writing out letters from scratch and through a good referencing system can connect different communications to each other. However, there is nothing in the contract as written which says this : sometimes Employers write in an additional option Z clause to say people have to use the proformas in the Works Information (which they then put in the Works Information) or an NEC cloud based system for contractual comms.
So on to your question of should the PM be issuing an instruction or CE or both. The reason for not accepting a drawing is that it does not comply with requirements in the Works Information or law - see clause 21.2 again. So if this is the case, then the PM does not accept it and states the reasons under 13.4.
If on the other hand, the drawings are in accordance with the Works Information, but the Project Manager - representing the Employer - just does not like what is going to be built then they will need to instruct a change to the Works Information and should, at the same time, notify a compensation event - see clause 61.1.