For those of you who are worried as hell like me about the 120-day working limit mentioned on the "WP-EXT for PGWP" letter, I believe there is a sentence that we can rely on and work even after 120 days if a decision is not made on our applications. I know a few people who are already past 120 days and still waiting.
Please refer to
this page which states
Letter validity
Officers should understand that the validity date of the letter
in no way overrides the authority of paragraph R186(w), which allows foreign nationals who meet the requirements to continue working until a final decision is made on their work permit application.
The paragraph R186(w) in the paragraph above refers to
this section which states:
186 A foreign national may work in Canada without a work permit
(w) if they are or were the holder of a study permit who has completed their program of study and
(i) they met the requirements set out in paragraph (v), and
(ii) they applied for a work permit before the expiry of that study permit and a decision has not yet been made in respect of their application.
So it really depends if you meet the requirements in part (w) and (v). The 120 days seems to be a service standard for in-Canada applications and does not override the paragraphs above.
Nevertheless, I'm not 100% sure if this statement is enough as proof, but at least it's something that you can refer to from IRCC.
I wish we all receive our PGWP soon!