Sometimes if you started the computer and happened to bump the mouse the optics consider that movement a 'starting point' of when the mouse is still, similar to how if you started up a ps2 with the analog stick in a certain direction it would start moving in the opposite if it returned to center.
I would try ensuring the pad is clean, the laser is clean i.e. compressed air/microfiber alcohol wipe around the laser on the mouse, unplugging the mouse, then finally restarting the computer.
If that doesn't work, try uninstalling the drivers for the mouse, restart, reinstall drivers.
If that still doesn't work, try plugging a different mouse in, if it's only with the Naga then the Naga is the issue.