For refugee PR, yes, they cannot have a passport renewal. Even they can, they avoid doing so. This is a reason for them to get protection.
Most of them go travel after they got Canadian passports. Their visit back to their motherland is still in question.
There is a very lengthy, in-depth discussion regarding the risk of losing status in Canada that PR-refugees face if they engage in acts constituting grounds for cessation of protected person status, especially reavailment. See "
Refugee status cessation and PRs applying for citizenship" here
https://www.canadavisa.com/canada-immigration-discussion-board/threads/refugee-status-cessation-and-prs-applying-for-citizenship.333455/
No need to wrestle with that subject here (you might notice I am, well, one might say,
acquainted with that subject).
The point, which should be simple enough, is that obviously PRs will be issued new PR cards even if they do not have a currently valid passport. I referenced PR-refugees just as an obvious example.
PR cards are not like visas. They do not depend on and are not appended to the individual's travel document (typically but not always a passport). Again,
@Ponga has this right.
A PR does not need to renew an expired or soon to expire passport to be eligible for and issued a new/renewed PR card. (Foreign Nationals, in contrast, generally must have a valid passport to be issued a PR visa, with some exceptions.) Remember, the PR card is a "status card" NOT a travel document (even though it is used in conjunction with a valid travel document, typically a passport, to board commercial transportation destined for Canada).
Acknowledging that in individual cases
stuff-happens-stuff sometimes happens.