this has happened to a friend of mine as well. He also filed a few successful claims with the same property and was then contacted by a staff of that property telling him, he should cancel the nights, he will not stay there.
After he told her that he will stay there and will consume all BRGs, IHG closed his account as well. Afterwards he found out that it was the lady who may have pushed IHG to do so. Kinda wired as well, because he followed the T&Cs as u did.