I play on very low sensitivity (800 dpi, .121 aiming.pro sensitivity) and i find that fast mouse movements tend not to get picked up by the aiming.pro training app. This generally isn't a problem in other games. Is this something that's fixable? I've tried increasing my dpi and decreasing sensitivity and the skipping still happens. It makes the exercises that require large movements pretty hard.
Yes, it's due to a bug in Chrome that leads to random mouse skips. We have implemented some code to fix this but it causes mouse lag at lower sensitivities. Unfortunately, we don't have a permanent solution until it gets fixed in Chrome but you can try halving your dpi and doubling your sensitivity.