If you move a tire in a interstage during building, the tire will do all it can, to get out of the interstage. Placing Tire directly in the interstage does not end in the same (chaotic) result. The same goes for tires, that get retracted in the intestage.
Just retract slider1 and see what happens
(The can on the side is just to show, how the two cans got built)
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