William Easton

I've been able to recreate this in 1.16.3. It seems like the entity distance affects this, unsurprisingly. I haven't been able to do this with normal glass though, just stained glass and stained glass panes.

I can confirm, I have also seen this multiple times.

I was able to recreate this, a simple way to recreate is by flying away from any land in the end and summoning a shulker. It will stand in the void as if there were a block below it.

I disagree thcrafter06, this isn't a feature request, this is pointing out something present in the game which may or may not be intended behavior, as it allows for the equivalent of an "MLG water bucket" with twisting vines.

You did not provide the correct arguments. I suggest you go to https://minecraft.gamepedia.com/Commands/stopsound to find out more about the command.

I was able to recreate this in survival and creative.

I also managed to recreate this with a crossbow and somewhat with a trident. To consistently recreate this, type in the command "/summon arrow ~ ~3 ~". This will cause the stuttering arrow glitch every time, though you must be in creative.

I was able to recreate this in 1.16.2 with and without Optifine. Also, it can be done when you aren't on a horse. It seems to only happen in creative mode, and it doesn't matter the exact angle you fire the bow at, just that you 'catch' the arrow with your head.  

Couple questions about the situation:

Did the horse have armor on?

Did the bow have any enchantments?

Were you aiming directly upwards when you were firing?

Can confirm that the spawner minecart has no mob inside of it, but does spawn pigs.

I loaded the seed in a world and the stronghold was right where it was supposed to be. My guess would've been that you turned "Generate Structures" off in the world creation menu, but I tried doing that and the locate command didn't work. So, I've got no idea what happened to you. Maybe just some botched world loading?

Would you mind posting the seed of the world this is in?