A builder of mine went to sleep in a straw bed with a block ; most people take blankets or teddy bears, but whatever floats your boat, gnomey.
However, since the block was not "dropped" (equipment shows carrying Marble Block) and was the neareast block source to all construction, all the rest of the builders are stuck on the same square are trying to acquire it, and failing.
I now have 3 gnomes stuck in a bed (cosy!) and two permanently flashing green construction points. I will cancel all block construction, but the bug is reproducible.
Surely gnomes should drop their current cargo before heading to bed?