Resource packs work in singleplayer, but when in multiplayer, they crash. 

Packs of note: FoxyNoTail's Mob Heads and Mini Blocks packs; work fine in singleplayer crossplay with host of windows 10 and 2nd player on xbox, but on realms, it crashes Xbox when downloading resources (Works successfully on Windows 10). 

CornerHard mentioned that this was fixed during the 1.16.200 betas, showing a successful playtest of the packs on the internal testing engine (in discord DMs), but once the update released, it was still broken.