WAI
WAI, as zombie villagers are just a sub-class of zombies.
You can use an online video compressor. Please attach a video.
There is a known bug where lighting breaks when entering from another dimension (MCPE-69037). Also, the bug where lighting might not transfer over chunk borders seems to be in effect again.
In 1.16.0 (the release version) the blocks get fully deleted. This also affects dragon eggs and anvils. Please update the report.
MCPE-69037