I have an appletv 4k as our primary living room channels client, and for a long time now - at least a year or two - we'll occasionally launch the channels app only to find the left-hand/main menu missing. No matter what kind of buttons are pressed, the only way we've found to bring it back is to exit to the appletv home screen, double-click to bring up recent apps, and kill channels. Then go back and relaunch the app again and everything is back to normal.
This is always when first turning on the TV and appletv after they've been off/sleep awhile.
I run channels clients on a couple firesticks and an Nvidia shield, and I've never seen it do this on them.
I have been promising the wife forever that I'd report it, but I finally got her trained on how to fix it, so it hasn't exactly been at the top of my priority list lol.
I'm curious if I'm the only one seeing this though. It's a minor annoyance in the grand scheme of things, but felt like I should probably mention it.
Thanks!