So... how come I can't turn my screen off while listening to music anymore?

[kabuk1]

I don't know why, but all of a sudden I can't turn off my screen while playing music anymore, and my TP no longer goes into sleep mode during playback. It just stays on. I have always been able to just hit the power button with no problems in the past. Coreplayer stops playing till I turn the screen back on, TF3D player stops as well, as does every other player I have tried. Nitrogen, TCPMP, Pocketplayer, etc. Anyone have any ideas why this is happening? I'm running Mighty 4.16 & using the stock adapter & sometimes the stock headphones. This problem just popped up recently. I did search before posting this & found a bit of info, but no resolutions.