Just got back into the game since launch. The mouse keeps drifting over to my second monitor, even with full-screen mode enabled. No mods or anything, fresh install. Anyone know of a fix for this?

Playing with 3 monitors myself in Nvidia Surround, this issue tends to happen if you got another game or other programs that runs in windowed mode. Never seen it when playing in fullscreen though, as then my left and right screen just goes dark if the game doesn't support ultrawide resolutions.

Try playing CP77 in windowed mode, and if the mouse cursor leaves the game screen again, try using Alt + Tab to switch out of CP77 and back in to it again. Click in the game window with the mouse cursor to make sure.

To Windows, this will technically first set the game window as inactive (meaning the mouse cursor will move freely) and setting it as active again. This should lock the mouse cursor to the game window.

So I found a solution that worked for me and figured I'd post it in case people in the future have the same problem;

Go to the cyberpunk 2077 folder and delete the bin folder, then go to the GoG launcher and run verify/repair in the Cyberpunk menu.