I never heard about such requirement before. When I moved to Montreal 8 years ago I had been Ontario for five years. And I was still a Landed Immigrate. I applied for COFI and was accepted. I did not have economic assistance because I had a job. However, I was told that I could have some if I did not work at that time. I do not think that this policy has been changed. Each year there are hundred and thousand people moving cross provinces for jobs. What would happen for them if the policy were changed?
For a Canadian resident, you can move to anywhere you want. To call a province as your home, you have to be registered. That means you must apply that province’s Medicare card. You should apply the Medicare card as soon as you landing or moving to a new province. If you already got one and moved to other province, before you receiving the new card you can use you old one to pay your Medicare bill. It should be valid at least three months after you moved out. But you can not use both Medicare cards simultaneously.