Title says it all, for info:

micdoodle8/Galacticraft#3385

I am experiencing the same issue. Please don't be too lazy this time about this, The Betweenland is a nice addition to MC. Finish the coding before adding features.

This was resolved 20 days ago there hasn't been a new release yet. In the meantime you can try a pre-release build, which are not stable so be sure to keep a world backup.