This is a very rare bug that I couldn't reproduce after I stumbled upon it. Thankfully I was able to record it happening.
In case any of this info helps, I will try to describe how I found it. In a Pillager Outpost, I was making a sweet berry bush farm, then a Pillager and a Skeleton was about to walk into the structure. When the skeleton came in the Pillager pushed the skeleton into the berry bushes while it was trying to walk around them.
Then this happened: https://drive.google.com/file/d/1782zOz1yuFThSOg97fDukjWsemRcugW_/view?usp=sharing
It didn't take damage after moving around like that until I touched it. Very peculiar.
The best way I could recommend to reproduce this is to:
1: Find a Pillager Outpost
2: ALMOST cover it with sweet berry bushes
3: Make sure it is day time
4: Spawn an Un-dead mob
5: Observe as the mob tries to escape the sun into the Pillager Outpost.
6: It should get stuck here as it tries to avoid it while entering the shade:
7: The result should be something like this:
Thank you for your report!
We're actually already tracking this issue under MCPE-56142 so I've requested this report be resolved and linked as a duplicate. I realise your report is older and you've done an amazing job at keeping it up to date, but it looks like the later one was noticed earlier and has been confirmed and given an internal Mojang tracking number.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
Thank you so much again for your dedication to the ticket.
Ionic
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