Issues with games capturing the cursor

[Flaminel]

Hello,
So I've recently found out that games do not capture the cursor of the mouse anymore. Found out the hard way while playing PUBG and while in combat. My setup is as follows:
- On my left: Lenovo Y720 Notebook with an I7 chip, 1060 6GB, ADATA XPG SX6000 Lite 512 GB SSD
- In front of me: LG 24MP59G-P FHD monitor
I'm always playing games on my LG monitor and yesterday ( or idk when this started really, but didn't see it until yesterday ), while playing PUBG (while playing, not only in the menu), I've noticed that my mouse is going outside of the game while looking to the left. I thought it might be because it was in borderless fullscreen, so I changed it to fullscreen, but that wasn't it. I thought it might be the game, so I fired up CSGO to give it a spin. Same happens while in menu and while pressing TAB in game, but not when playing ( thank God at least this one works ). I've tried some app called DDMM to help me with PUBG, but the mouse is still getting out of my main monitor before the app puts it back. Please do let me know if there's anything I can do to revert this, as I've never experienced this problems before.
As a side note, yesterday I've bought a pair of Marvo HG9028 headphones and installed its driver, but I've already uninstalled and unplugged to see if that's the problem and it isn't (or it might be but idk how).
I've got exams for my bachelor degree next week so I'm not in the mood for reinstalling the windows just to see if that solves it.

[Flaminel]

So... no idea?

[Johnny Relentless]

U use a second monitor or virtual display or tv?

[Johnny Relentless]

Then like you said its maybe the fullscreen ! Look for all option that scales the picture ! Game side ,driver side , monitor side