Bug/Issue Game lags out when a notifications pops up

For reference I have the Steam edition of the game (idk if this changes anything). Whenever I get a notification, open another app, or alt-tab out of the game (anything that causes anything except the game to appear) while it is still running causes the game to lag out. I can still move around (if I have my sound on I can hear it) and open menus, etc. But my screen is frozen on the last frame that was showing before the notification popped up. I don't have this issue with any other games (Steam or otherwise) on my computer. If I close the game, it reopens in the lowest possible resolution (I think 800x600) instead of the resolution I play in (1920x1080). I can change the resolution, but then have to close and reopen the game to apply the change. This was not a problem until I was fighting Asra Nox, defeated him, and then this happened and I had to do the whole fight over again. This has happened multiple times while I was doing anything in the game. I am on Windows 10 Home version 1903 (OS Build 18362.900). The only mod I am using is the Summer Sale Soda Mod, which was an exploit mod for the Steam Summer Sale 2019. I am using fullscreen mode. If anyone knows how to fix this it would be greatly appreciated.