Custom Items(such as weapons, guns, foods etc) do not load/show up after 1.20.30

Pretty much makes me unable to make smp's/worlds or addons with custom codes and items even when experimental features are turned on. Dont get me wrong Mob scripts still work but custom items do not work.

Edit: This also sometimes affect Educational Edition .eg. The custom blocks hydrogen etc. wont show making it impossible to do anything in Education Edition also.