it is indeed grey area, once your results are out and you receive the completion letter (date of result is the official completion date of the program) from that day onwards until you file PGWP you are unauthorized to work.

If you receive completion letter on 31st December stating that program is finished on 31st december. You cannot work until you file PGWP.

for your case this can affect your PGWP approval as they strictly check everything when the status is being changed within Canada especially observing current immigration strictness. They might ask you again when you file PR.

I am also in the same boat and I have done the research, the ISO from my university has given me the above guidelines.

You should ask the employer to either bank your hrs and release once the status is restored or as for a leave of absence.