I just saw when using the Onstep app on Android (tablet) that the N / S direction was random.
Let me explain: I press the N key, the telescope goes south. I press the S key, the telescope goes south, I press the N key again, the telescope goes north. After all is back to normal. The case is random and does not always do.
Sometimes it is enough to press the E / W keys (which have no problem) for this to happen again.