I don't know whether this is some kind of a report bug, but the system battery reporter says that some applications, which I only use for sure in the foreground and are either on restricted or optimised, stay in the background for multiple hours: Take for example my browser, which I had for 2min. on my screen, but then stays in the background for >1 hour. The other day I used it for 45 min. and it stayed in the background for about 6 hr. 30min. This also happens to many others applications and I don't get why that is the case. I immediately close all tabs.