We're just back a 12 day cruise that became 19, as we succumbed to Covid in day 10 and weren't allowed to disembark due to Maltese regulations.
We stayed in our original midship balcony until the evening of day 11. They then moved us to R746, also a balcony, so that they could disinfect our old cabin and give it to the next customers to have booked it.
The back of R deck (or at least the even numbers) seemed to be reserved for those with illnesses. There were rather a lot of us, by the looks of it.
Once we were released from quarrantine we kept R746 "as long as P&O don't need it for other Ill passengers" - and there we stayed until our return.
It seems ungrateful to complain but there was a heck of a lot of mechanical noise in R746 when docking, presumably from the side thrusters.