DDJ SX and Rekordbox big issue

Hi everybody, hope that you are all good, quick, I have ddj sx and it works virtually perfect on serato. With rekordbox 5 big issue When start playing it does not react on FIRST lifting volume fader. And after around half hour of playing music happens the same, lifting volume fader does not react. (That is I lift volume fader but the music cannot be heard as it should if it was working properly.) This is a major issue because i want to use it on a gig. Please any solution? Best rerds, Aleksandar