Why Does My Apple Tv Shows An Inconsistent Resolution Even After Hooking It On Lan Cable? Here's The Fix.
Did you check your video resolution in settings? You may need to change the default streaming for video quality. Your internet may not be fast enough.
There is also a possibility that your Apple TV is defective. How old is it? If it still under warranty, I would bring it into Apple and see if they can replace it.
My Apple TV would occasionally lose resolution, but it would correct itself after about a minute. Does your TV correct itself? Internet speed does tend to fluctuate depending on bandwidth usage and peak times, so if it’s for a few seconds to a minute, I would consider it to be normal.
If it stays that’s way, then it could be a hardware issue.