While loading a 1.13.2 world into 1.14-pre5, the server freezes at
"Preparing spawn area: 0%".

There are no exceptions and the process has to be terminated.

Loading the world into the 1.14-pre5 Mojang server works fine and fixes the world such that it now works in spigot as well.

I have attached the log file and a minified world that reproduces the issue.