The carbon ring is not a tight fit on the shaft. Even a new one will wiggle like that. It is the bellows pushing the ring against the ring seal carrier that creates the seal. That's why the condition and alignment of those two faces is so important.
Odd that your PTO came loose. I've not had a single issue with mine since installing both with anti-seize. But the engine should tighten it, not loosen it. If it loosened they would all fly off on the first run.