0.76.5 experimental character becomes unresponsive

[Sicdoc]

When building walls one or more characters become unresponsive, if picked up and put down again they go back about there business or a reload also works. I also notice that if a character has a full inventory they can't do their requested job but there is no way of knowing what's wrong unless you figure it out for yourself. Maybe a little speech bubble letting you know would be helpful, especially for new players. Also here is my latest crash dump.