You have to understand that any formal communication between the department is through memorandums. They may be accepted, rejected, accepted in part, etc. If they are accepted, it will become a formal practice only when it is notified.
Eg. When IRCC started prioritizing the CEC and inland applications, they all would have started from a memorandum sent to the deputy minister or minister of immigration.
Since this memorandum was never notified, I would not hold it in very high regard. However, any internal circular, cabinet note, or notification, subsequent to this memorandum is what would matter.
It is a well-known fact that the processing of the outland applications was paused for many months, and it was in response to the workforce issues and IT issues IRCC was facing as stated before the Parliamentary Committee on Immigration and Citizenship. Also, even if this memo were to be valid and effective, it is expired, unless a new one came into existence. This is why when looking at any info, it has to be seen from the complete perspective and not just one document. Whether there is any notification further to this memo, is there a policy circular in place, if so, when and when it expires, has it been renewed, etc.
Currently, as travel restrictions ease out and more countries open up where the local VOs are, more PPRs and processing will take place.
Conclusion read this document for what it is. Had it been the golden egg, it would have been on IRCC's website, and also see the last few lines, that talk about notifying the clients, it never happened. There was no mention of 90 days anywhere.