So 45 minutes after analgesia he started eating again ? To me that clearly indicates he has pain. Obviously I can only guess, but I suspect the pain is arthritic in origin. He could have over exerted himself when playing on the patio. Then after resting on the couch he sort of 'seized up' and was all stiff and uncomfortable. I have severe arthritic pain myself and I can assure you that it can be far worse after being sedentary for a while. As long as I keep moving the pain is not as bad. But first thing in the morning and after sitting down for more than half an hour everything seizes up and the pain is a lot worse.
As you know arthritic Rabbits frequently get gunky ears. This is because their ability to scratch their ears/groom them is likely to be significantly impaired.
You describe his not eating episodes as 'stasis', but if he still has poo output then he is not in full gut stasis, but pain related anorexia which if left untreated (with analgesia) would eventually lead to gut stasis. I think if you can get him on to a therapeutic dose of analgesia, perhaps adding another type of analgesic as well as Metacam. Also maybe add some complimentary treatments (under Veterinary supervision) such as massage, acupuncture, laser therapy his not eating episodes are far less likely to be an issue.
As I have said, all this is just guess work as I am not a Vet, so I would talk this all through with your Vet and see what she thinks