A word for when a machine or process occasionally misses a step

I am looking for a verb that means that a process misses a step occasionally.

This would be for a case where a machine or process sometimes, but not always, produces incorrect results. For programming code this is not necessarily because of a logical bug in the code, but because of e.g. the software application not working optimally in the OS environment it is used in. For physical machines this could probably happen because of some tolerance of a lever or something like that.

Is there like a way to say that e.g. "the machine is [insert verb here]"