He had to leave the country to get a newer stamp on his passport. My sister’s hubby had to do the same thing. He lived at her place for 360 days, then they had to go to the states and return with the new stamp on his passport so he could apply for his permanent resident’s card.
It’s common.
If he had to leave because he had been here six months, and turned around at the border after getting his passport stamped in the US, immigration might have smelled a rat.