See https://github.com/PaperMC/Paper/issues/1223
Should fix Vanilla bugs
Minecraft is saving invalid entities to the chunk files.
Avoid saving bad data, and also make improvements to handle
loading these chunks. Any invalid entity will be instant killed,
so lets avoid adding it to the world...
This lets us be safer about the dupe UUID resolver too, as now
we can ignore instant killed entities and avoid risk of duplicating
an invalid entity.
This should reduce log occurrences of dupe uuid messages.
Also reduce the logging spam overall.
Aikar