I'm glad you liked the look! That's definitely a weird issue, were you using a mouse or a touchpad? Do you have any sort of controller plugged in?
We've had it run on Mac using firefox or a chrome-based browser without issues but I'll have to see if I can find anything on our end that could be causing that for some machines. It sounds like it's reading some sort of input that it shouldn't be, I'll have to see what I can find.