Red led doesn't go even device is closed

I bought studio3 yesterday it came with nearly %85 battery while i was using it red led lighted i tought battery is low and pluged it to cable to charge after like 20 minutes 5 white leds are lighted i checked it from app too %100 percent battery charge but still red led is lighted even i turned my beats off. Left it like that at night in the morning red led was gone but when i turned it on it came back.

When i look for battery percentage by clicking the button at right cup both red and white leds light.

I don't know what does that red led means.

I searched it everywhere but couldn't find anywhere