Kirill17

Can confirm

Can confirm 

Can confirm 

works as intended according to slicedlime video and the simple logic that non player entities teleports instantly upon entering a portal 

This seems like intended behavior given the nature of the enchantment, it's usefulness and it's only actual use in commands

Can confirm too 

Can also confirm 

MC-13118 

This being marked as WAI goes against what was previously intended behavior.

Can confirm 

I would let Mojang determine if this is WAI as they have already confirmed the bug and not marked it as WAI. Furthermore in my previous comment this affects iframes as well as other cases outside explicitly invulnerable mobs. I don't think a deafening annoying noise would be WAI. 

Hey you can check is cloned by or click here for the valid bug report
MC-268420

I'm not entirely sure though if the remainder of the bug would fall under WAI though? This happens during invulnerability frames. Whilst the other bug report only mentions explicitly invulnerable players or entities where it is explicitly made so the entity cannot take damage

 Iframes are different. 

Made a video showcasing this happening at both 30 attack speed and a higher number in survival. You can see the indicator flashing quickly whenever slots are switched. https://youtu.be/cqFtRG_i_RQ
This should be a issue that affects most servers which utilise this. 

Hey the number is just a number for the command, the game puts the highest valid attack speed onto items irrelevant of what the number on the end is. 
Furthermore even if it 10,000 isn't a valid value, the game still applies this number visually to all weapons and items the player has when the command is run. Using a more valid number of 30, this issue is still a thing. The cooldown indicator disappears for the main hand and all items but flashes quickly whenever switching a slot. High attribute speed or low attribute speed so long as the attack speed is high enough to remove the cooldown(which happens around 26) the bug appears. 

Can you provide the crash log if any? i'd like to see what is causing it considering you aren't that very descriptive in the exact events? Along with this the game's log?
To get to it do the following assuming you run minecraft within .minecraft and use a windows computer 
>Press windows key + r
>Type in %appdata% and enter following it
>navigate to the .minecraft folder
>click the folder logs and crash and send the latest log from the latest crash
Usual directory is as follows, with the inclusion of your pc's name
C:\Users\<name>\AppData\Roaming\.minecraft\logs
C:\Users\<name>\AppData\Roaming\.minecraft\crash-reports

That isn't a glitch
If no exit portal fountain isn't there when you first upgrade to later mc versions or load the end and you place a end crystal near 0 0 it'll load in one

Beacons are already full blocks
Frost ice and ice are already full blocks
Barrier,glass,leaves and spawners,slime blocks and shulker blocks are all full blocks
Please remove them from your list