M65 Laser Tracking Issue - Defective?

I'm having a tracking issue with my M65 mouse and think the laser sensor may be defective. It has never worked properly. When moving the mouse around, the tracking speed varies from normal to not at all. It is especially noticeable when changing directions. After lifting the mouse and putting it down again, it tracks properly for a few seconds and then slows again nearly to a stop. I have tried updating to the latest firmware and adjusting the settings in the software, but I keep having the same issues. Has anyone else had these issues? Is my mouse defective?



Thanks,

Dan