Forge Building stopped

When building the forge, all workers stop working when it gets to a certain point. Unable to start new forge

Steps to reproduce:

  1. On the save file, build a new forge work never completed

Expected Results:
Forge to complete
Actual Results:



Version Number and Mods in use:
no mods, alpha 20
System Information:

Sorry, apparently “New users can’t upload attachments.” So no save file.

my game has same problem. after finish build “the forge”, they never get off ladders and other wood construction.