Brightness cannot be controlled after a while in Dell Inspiron 7559.

Hey, I bought the Dell inspiron 7559 (windows 10) a month ago. Then i decided to get insider updates and since after i started receiving major insider updates i'm unable to adjust my screen brightness after around 20 mins of continuous usage and the brightness remains still(i.e. if i set the brightness level to 5 then it can't be changed unless i restart my system) . The insider update i'm on is Build 15031.rs2_release.170204-1546. Also i though that resetting might help my problem but instead it completely rolled into the (Windows 10 Home Insider Preview) and i can't revert back. Please help me. Thank you!