They can't "stall" as that means it doesn't have enough momentum, as they are powered all the time this is not the case. They fault, this one way more than a certain other one in the UK which has done this once this year. It faults and for whatever reason wether it's a faulty sensor or overspeed etc, causes the fault and tells the ride to slow down and stop at its earliest convenience. It doesn't matter which side it stops as long as the ride stops. As I said though Kobra appears to be having a lot more issues than Edge when it comes to this. They have tried many things on Kobra I believe to reduce the faults, one of them slowing the ride which has caused it to behave a lot better.