To my knowledge, it wouldn't care if you applied for PR before Dec 9/2020. In my case, as example, I applied in June/2020 and my MPNP nomination expired in Dec 27/2019 and there was no issue (it all worked fine). However, I'm not sure if there was some recent change.
I can recommend an immigration consultant to send question online (he should be more up to date in terms of changes, and know how to answer more custom/specific questions as well he can review your application when u go apply for Bowp ):
https://jpimmigration.com/work-permit-canada/bridging-open-work-permit/