Certain Apple devices have been continuously disconnecting from AirPlay after the TVOS 14 update on both wired and wireless LAN connections.
Problem:
The problem occurs in Safari when scrolling YouTube videos forwards/backwards or trying to Airplay YouTube videos after the video has already started. YouTube videos will sometimes play and scroll successfully with the Chrome browser.
Solution:
Upgrade MacOS and/or IOS. This problem does not seem to occur with MacOS Catalina and IOS 13 or above.

