Both players are showing the Blue sync lead master light on at the same time (top right of the screen the one with the Green sync light next to it), there should only be one on at a time. You should also be able to choose what player is the lead player at any time but when it has this fault you cannot. Plus when one player stops the other becomes the lead automatically, this does not happen when it has this fault still both players stay as the lead one at the same time no matter what buttons you press. Also turning off the sync button or master makes no difference whatsoever.
The only way to clear this is to power everything down and start again as while this fault is present you cannot mix. I have only encountered this issue 4 times in six weeks and have done some in depth testing of my own to try and find what the trigger point is but so far no luck plus numerous emails (and a video of the fault) between myself and Denon’s support In-music but still no joy.
So if anyone knows what causes this PLEASE tell me also if you have experienced this please put it on this page and tell Denon’s in-music technical department. They say it’s what we should do as the forum is monitored.
NoiseRiser is correct but what I will add to what he has said already but with just a little more detail. You said you have have to push the pitch fader all the way up and down, that’s not the case what ever direction the arrow is lit up on the pitch fader move the pitch fader slowly in that direction and when you reach the speed that the tack is playing at the light will go out and you can then readjust the speed of the tack gradually. As NoiseRiser said soft take over.
Opp’s I missed that partly as I don’t like this additional light over the wave form. I do turn it off in the settings but it come back on again on it’s own. Yes I have logged a fault and they are looking into it I even found out what triggers the fault for them.