Application for Canadian PR along with US Green Card 485 / EAD

Posting for a friend of mine, who is interested in applying for Canadian PR.
He has applied for US GC on EB1 and got the EAD. All he is waiting for his priority date to be current, which seem to have retrogressed to 2016. (still better than EB2)

Is anyone in the same boat or knows someone who has that situation?
Are there any legal/negative implications of applying for Canadian PR (or for that matter any other country’s PR), when you have already showed immigration intent to USA?

Thanks

I don’t think that would affect their GC application in any sense, but if they already have EAD and on EB1, then applying for Canadian PR would make a lot more sense only if they intend to settle in Canada.
I don’t see many advantages of going the Canadian PR route for this case(EAD approved), if they intend to move back to the US once their GC priority date becomes current.

I know there might be other advantages or scenarios I can’t think of, but happy to see what the community has to say.