Reply to Out of phase sound when playing same track on 2 decks, same settings on Traktor Pro 2

Hi

Is it normal that, when playing the same track on 2 decks, that it sounds kind of flanger-alike? like there is some sort of phasing going on. The track is sync'd on both decks. Sometimes it doesn't do it, sometimes it does.
And making it in phase with the jogwheels/tempobend don't seem to work, still sounds bad.
SNAP is on.
Pressing the same quepoints on both decks at the same time rarely does a perfect timing. I'm not doing terrible off-sync pressing of buttons.
I'm on traktor pro 2.6.0


Any ideas?