Brother, The rules are clear, if you are a Canadian Citizen you can stay in Pakistan while your family sponsorship application is in process.
You may be asked to provide proof of your genuine interest to return to Canada during the process for which you would require to show evidence such as rental agreement, funds in Canadian accounts and preferable a job letter or interview but that will be in future and they may not even demand it. The reason they do that is simply to make sure that new immigrants (your family) is not using Canada for medical treatment and social benefits only.
The reason a Canadian immigrant (permanent resident) cant live in Pakistan while his family sponsorship application is in process is due to residency requirement for an immigrant (since the person is not a Citizen and may lose PR if residency requirement is not met) and CHC-ISB does not make that determination that is CIC Canada, other than this reason it is simply the law of the land
if you are a Canadian Citizen and going to live in Pakistan after your sponsorship has been approved, better dont bother updating your own address to CHC-ISB, they wont know it unless you tell them, it also depends on your case that if you need to provide proof of ongoing relationship where you have to let them know that you are living together or if you have already provided proof of established relationship to CHC-ISB.
You may also like to apply for a visit visa (in case you dont have children) for your spouse, it may work and you may not have to migrate back to Pak during the proecss
Hope it resolves the confusion
Thankyou brother for trying to help but the confusion is still there. Canadian citizen cant live out side in any country for more then 06 months. Please check the law. Because we are pakistani national that why we can live in pakistan. If we try to live in any country we cannot live more then 06 months.
As a PR resident the situation is the same PR also canot live more then 06 month out of the country. But PR has to live in the country I dont remember the exact years to maintain his PR status.
Simple is that if some one live more then 06 months then he/ she canot filed a tax return. and also there are some more problems for example if some one have a kids and he/she is getting child benift. They can get for 06 months if they are out of the country.