Realistically speaking - anything could be a reason. A shakedown or blocking based on some "nudge" (this might come across as tin-foiled though). Some flag/trip-wires going wrong, more worryingly due to a bug/false alarm - and this is more worrying because in this case semi-incompetent large orgs like MSFT find it really hard to accept it, fix, and move on. Some change in OP's account that either they don't see or haven't realised - some edge case, you never know.

And of course, it doesn't affect their earnings and there are no consequence, or significant, so they won't care and won't respond or tell what went wrong.

Can one move legally? Sure. But then it effectively is a combo of who blinks first and who can hold their breath longer.