Owen Knox

Also, I should make a better note on my first comment, as to say the entity stops movement before you hit it, but hitting it creates the inability to take damage and etc (confirms the state as I call it).

The best relation I can make is that it is almost like going into the entities' data and turning NoAI to 1, as the behavior seems to be the same (until relog). Undead mobs don't burn, entities float and stop making noise, children don't grow up, items don't follow the 5 minute rule, and no damage gets taken, although that does not seem to be the case.

Sometimes the entities (including items) do not need to be hit, just existing can cause this bug. I've had it happen with dropped arrows, as well as random monsters I see. They also stop making any sounds

This just happened to me, but I didn't even die. I was attacking a zombie and it just stopped working, but other things work fine (my wolf, a nearby skeleton).

EDIT: F3 + A did not fix, but reloading world did

Something similar to this, but slamming the ground (any chunks, unloaded and loaded) in 17w13a does the same thing. Stuck in flight mode, various results ranging from seeing through walls to odd movement.

Yes. Thank you. I will update all my commands now.

I re-tried the spawning the zombie, with the updated command and the zombie still only drops flesh.

Actually, heck. I'll re-try this.

Whoops... I pasted the command wrong. Let me fix that.