My Dad and his fiancé's cruise in mid November, which was to be QM2's first voyage back in service again, is one of those cancelled.
According to a letter Cunard sent to another passenger that they then posted on social media, QM2 will have to go into a quarantine of sorts on arrival into New York on her first transatlantic after the pause in December, meaning that passengers will get another two nights onboard but alongside at no extra cost before being allowed to disembark by the authorities after the authorities do whatever they need to do. If this was also in place for the cruise my Dad and his fiancé were on, a 26 night roundtrip Caribbean also calling at New York, it could've disrupted the rest of the cruise too much which seems to be why Cunard have cancelled it, in particular, outright.