"I tested it by using all 8 droids to build the same building at the same time, and none of them got stuck"
I would recommend testing it with all the droids doing different things in different directions. This is usually what I've been doing when I get stuck droids. I also wonder if it's possible for them to catch on the wall when they're going in and out. I have noticed they tend to hug the wall rather tightly and catch a bit when going in. I remember seeing single droid jams in previous builds, and usually when these happen it's when the droid is trying to go out. I'm wondering if the walls inside the warehouse are causing these single jams?
Also, I just realized you made it that the middle mouse button can be used to turn the camera for different angles. Can I recommend adding this to Q and E as well, where Q moves the camera around its pivot to the right (thus turning left) while E is the opposite?