Issue description
I have a connector in my concrete slab setup which always keep holding 2 concrete slabs, despite the fact that the belt ahead is empty

Not sure if its bad behavior or just a bug.
Reproduction steps
I have no clue what happened, my guess is that I added a 5th concrete mixer to the setup. Not sure if that's what triggered this thing.
Game version and build number
Update1 v0.5.5a (b250)w
Operating system
Windows