Basically, the world will load if it has already been made, but if you move it crashes. If you try to make a world with the feature enabled, it ends up like this:

Here is the crash report:
crash-2021-05-09_12.11.44-server.txt

The world does load fast though with threaded feature generation on!

Unable to reproduce with [email protected]+alpha.1.24, starlight, [email protected]+efd1665c on Minecraft 1.17.1 Release Candidate 1

@QPCrummer we can disable threaded-feature-placement because most of custom gen mods (or plugins for the c2me port to yatopia) are imcompatible with this.
I have no idea if it could be supported in mods that have custom generation in the future.
Sorry, you will have to keep it disabled for now.