This one is particularly interesting to me. An agent told me today that it is fine to work provided the study permit extension is not refused. She actually asked someone on the background who I reckon is their advisor or something.
According to her, your study permit is valid till the day a decision is made about your application, and applying for a PGWP on that status basically means you retain your work permit privilege.
That was in contrast to what the first guy I spoke to told me.
Like you, he told me verbatim that we couldn't work. Then a second guy told me that IRCC isn't clear yet on the work eligibility since the memo (RE: working on implied status) is relatively new, but that they should have details within the next few weeks or months knowing how slow they can get.
To me it is safest to not work, but I can't see them enforcing any action on working since there is such a big question mark about that case. It was like how everyone was convinced you couldn't apply for PGWP on implied status for SP extension, which turned out to be false despite it not being on the IRCC website at the time.