This is somewhat similar to my recent ATV “scrolling is terrible” post, but something recently has made trying to change bikes on an ATV with the remote nearly impossible. It will occasionally select the next bike but is really broken on my system. Anyone else?
Side note, about 20% of the time when I pick up the remote to do something I will U-turn. I suspect the remote is registering a touch or something, but why and is there a way to prevent?
Ah glad to see I’m not the only one. From now on, I will carefully reach over while cycling, gently grab the sides of the remote so as to not do an unexpected u-turn. 
Of course when I need to do one quickly, because I want to catch on a pace partner coming towards me, the button on companion is ironically very difficult to actuate in comparison.
Same problem with my remote (old style 4k). Never was great but now useless. Lets hope there are no races that require a mid course bike change!
It’s a known problem that Zwift are working on. See Apple TV Garage Problem