Multiple hits

Using Yamaha dtx drums

I can record my Yamaha drums with no latency etc but have one issue i cannot seem to resolve, perhaps someone may have an idea…
Using an ipad with everything in the background turned off, plenty of ram and disk space, when i play the kick it adds extra hits, slow quarter notes at 90 bpm record ok, but if i play anything fastr or eigth notes it adds extra ones, anyone know what causes this and how to fix it?