All minecarts in a world get lost when switch from 20w51a to 1.16.5-rc1

Hello! This looks to be a duplicate of MC-211308, which was resolved as Invalid. See @unknown's comment on that ticket for more information.

Thanks for the information.

Fortunately, I had created a backup beforehand.

I was just not aware that all versions of type like this 2XwXXa run on base 1.17.

Ticket can be closed.