I had my screen set to never turn off, but after I ran the Battle.net app that was changed to 15 minutes (It only applies to the ‘While plugged in’ setting. ‘On battery’ setting does not change). I am currently on a new PC with Windows 11 but something similar was happening back when I was using my previous PC with Windows 10. Back then it was only when the Battle.net app was running that the screen would turn off after a while. This time, even if I change it back to never turn off, the app sets it to 15 minutes once I launch it again. And it doesn’t change back to never turn off once I quit the app completely.
Both PCs are gamer laptops. 11 is an Asus ROG and 10 is an Acer Predator.