Reply to s4 led problems..

hi, i cant find any info on this anywhere so ive decided to ask you guys. ive just purchased a traktor s4 controller second hand and bought it home, set it up and soon as i turn it on the 4 cue buttons on the b deck are lit up bright green and stay that way the whole time, the buttons work but the lights stay the same. also the play cue sync and shift buttons on the same side dont light up when pressed on the b deck, the seller says this didnt happen at his house..
any ideas to why this is happening.. or is the seller not being truthfull
thanks