Razer Abyssus v2

Seems like a hardware / mechanical issue than a software issue The wheel mechanics might be faulty or might not have a good contact with the internal hardware. The youtube video is guidance to opening an Abyssus, maybe you can use it as a reference to open the mouse and check the wheel mechanics calibration.

If you still have warranty - RMA it, if not you'll need to disassemble it and check the scroll contact with scroll wheel as @Sye_The-Vie mentioned. If it's ok, the switch may be faulty, but it's farily easy and cheap to replace it (needs some soldering skills).