Read back through the posts. When you pause YoutubeTV or Youtube the screensaver comes on. When you attempt to restart your show, depending on the length of the pause, if long enough it will fail to restart your show at the paused location. You are returned to the Main Roku Menu, not even still in Youtube, at which time Roku starts to load a random channel
There seems to be an odd work-around of using the "return to prior screen" instead of the pause button to restart which seems to start your program at the paused location. It will play for a few seconds and stop at which time you have to press play button to keep it going. This may only work for a certain time once the pause is pushed. It's hard to know.
There's also been a suggestion of changing your screen saver to certain screensavers solving the problem but I think these lighter weight memory using screensavers are just extending the amount of available memory.