Long press on iPhone / iPad

Technical background:

I'm testing my long-press JS code on Browserstack and none of the iPhone / iPad devices there seem to react to my code correctly. They all fire touchstart and touchend events at once the moment I release the finger.

What I need:

I'm not sure whether this is an issue on their side, so if anyone with an iPhone or an iPad could try and verify that when they long-press on the first .5s box in this jsFiddle, the box starts shivering as intended - I would be eternaly grateful.

Thanks for reading :-)