WIndows 10 Games keep getting alt-tabbed without my action

Hi,
I've been playing a lot of PUBG and TF2 recently. This mostly happens in TF2, but did happen at least once in PUBG. I'll be playing the game full-screen, and then all of a sudden I see my Chrome window. As far as I can tell, the only weird thing I'm doing is holding the mouse button (M1) for a long time, but that might not be the case every time. This is only a recent issue affecting me the last week or so, and I've been doing the same stuff for months. Any ideas? I downloaded this Active Window Log program, and it doesn't even show the active window changing from the game at all, so the whole issue mystifies me.
Thanks,
Scott

EDIT: For clarification: Avast is my antivirus, and I just ran a MalwareBytes scan and got nothing.

Try updating video driver, it may be out of date.

It's up-to-date, but I'll try and reinstall it when I get the chance. Standby.

Do you have any kind of macro input going on, like a keyboard/mouse programmer that some of the gaming devices come with?

Okay, so I reinstalled it, and the issue still occurs. One oddity I've noticed is that trying to maximize the game window right after the "alt-tab" occurs really throws the computer for a loop. It will just sit there and not maximize the window, sometimes even showing a spinning wheel. However, if I click on the browser or whatever screen is showing before attempting to maximize the game, it works totally fine.

No macros going on. I have a Logitech G500 mouse and Razer Blackwidow keyboard, both of which are a few years old. Maybe I should run a key-logger and see if the un-commanded alt-tabs are actually coming from the keyboard?

Sorry to necro a thread, but if I remember correctly, re-installing Razer Synapse fixed it. Something's the matter with that software... other times, it'll pick out a random key on my keyboard and when I type it, it'll either not type it or type it like six times until I close the application.