I have been getting a repeated bug since rekordbox 4.2.x
I submitted a ticket and technical support have not been able to recreate and I am wondering if anyone else has experienced.
For those who are not as familiar, master tempo on allows you to change the tempo of a track without changing the pitch/key. There's a button right above the pitch slider that turns this function on and off on CDJs and an "M" on rekordbox DJ software.
Anyways my master tempo feature ceases to function randomly 2-3 hours into my sets. The pitch/key of the song changes with the tempo. Pressing the physical "master tempo" button on the CDJ and the "M" in the software does not turn it on even when it is indicated as active. Loading new songs has no effect. As far as I can tell, the only way I can fix the problem is to shutdown rekordbox and restart.
I am using:
MBP Retina with OSX 10.11.6, Rekordbox 4.2.4, CDJ NXS2 with firmware 1.5, DJM NXS2 and DJM NXS. It has additionally happened when using the CDJs as my audio sources as well as the DJM 900 NXS and NXS2 as my audio sources.