So...me too. I have two ATV 4K still operating flawlessly in other rooms, but my 4th gen ATV in the bedroom died & I brought out my still-functional 3rd gen ATV while I wait for the next ATV model. All of my other streaming services are fine on the 3rd gen, even my music & purchased movies. Apple+ starts off OK but at 5-20 minutes into a show (The Morning Show is where I first noticed it) the video jumps back about 10 seconds And then continues on. The audio and CC however, continue on as though nothing happened, now completely out of synch with the video. I’ve rebooted router, rebooted ATV, & even reset the ATV (passwords, save me!). The problem continues to occur.
I spent More than an hour with Apple support on the phone. I did all of the things I’d already done multiple time, including another dreaded “reset”. I lost count of the restarts. The glitch is still happening. The tech suggested that my hardware seemed fine based on otherwise normal functionality. She stated that is a “software problem”. That means the problem lies between my 3rd Gen ATV and it’s implementation of the Apple+ streaming service. The question is: Does Apple+ Simply not run on this older hardware? If so, Apple should just tell me so I can get about a workaround (although I’d hate buying a new device just before a new model comes out).
This exact problem has been in the users forum since early November 2019 based on my limited research. I haven’t seen an official Apple reply. It’s my belief that some (maybe all) 3rd gen ATVs won’t seamlessly run Apple+ streaming services. I hope I’m wrong. Good luck!