On my last puzzle, which is the treasure, when my Master Builder began…

On my last puzzle, which is the treasure, when my Master Builder began digging, the first thing that happened was a scaffolding for a hut came up. Now they seem to be digging to no purpose...Master Builders, Trainee Builders, Adept Builders...they are all digging away, and producing nothing! Help!

Also, my adult villagers randomly carry rocks around the place, and I have to pick them up to make them drop them.