I wanted to make this post as because I wasn't able to find this solution anywhere online. I purchased Destiny 2 on my PC a couple months ago. Since day one of owning it I've had an issue when alt tabbing or selecting a different window if game is in windowed mode. Whenever I select the game or alt tab back into it, my character acts as if some of my keys are actively being pressed. It always seemed as if it was randomly hitting keys. Sometimes my super randomly activates, other times my character would be walking in one direction. When trying to google the issue for a fix, I found several posts with people having the same and weren't able to find a solution. After dealing with this for months, I sat down and messed with my CVARS.xml file, my antivirus, and GPU settings to no avail. Eventually, the one thing that finally worked was uninstalling Nividia Geforce Experience. I know a lot of people think that means it will uninstall the drivers. It will not. NGE has the ability of updating drivers automatically and help optimize games automatically. All of that can be done manually by going to their site to download updated drivers when searching for your GPU model and you can optimize games by adjusting the in game settings. Not sure if Bungie can find and fix where the conflict lies between Destiny 2 and NGE, but having Nividia Geforce Experience installed seemed to be that cause of this weird alt tabbing issue.