Try reloading resourcepacks with Ctrl+T when in the world (causes a bit of lag).
What's wrong? I think it's fixed now.
You can use Cheat Engine to slow down a game to see it better. My computer sucks and I can't record it btw. Maybe some of you can?
Please reopen, this is not fixed.
'Version 3 resource packs have to use lowercase filenames for everything' maybe it happens because of this?? Language codes look like 'en_US' but they must look like 'en_us'.
There is no NBT-tag for dragon head's mouth 😞
That's a different issue, mobs didn't behave like that in 1.12.2.