I am not sure about the rules exactly but "Having enough funds" rule is only applicable for Work permits, TRVs and dependant's permits as far as I know. This might not be applicable for PR. Once you become PR, you have the right to come and leave the country N number of times during your PR validity. So it doesn't make sense to expect a job or funds every time you travel to Canada. This is my opinion. But the best thing is to check with CIC call center agents just to have peace of mind.