Oh and now a new thing.
So I decided to auto-build a bridge.
And then make it extra bridgey.
Unfortunately, the bots did not take well to the experiment.
The nice convex portion in the middle went smoothly. But after fourth and fifth row, their little minds started to break. They stop placing parts and just... walk away. Into top left corner of the map. Here's two 'pilgrims'. 
There also is a third one that got much closer.
After a recharge, two of them settled down in a corner while one came back to work. I was just about to say that somehow it seems to only affect plank and pole bots, but here my log placing bot went off too. Buut one of the previously stuck bots came back.
So yeah. Fun.