I have observed there are residual trace "odors" of varying degrees of detectability left on traps from any of the natural dye treatments: walnut hulls, sumac berries, oak/maple barks, leaves, etc., including the logwood dye concentrates - chips, crystals or powders. These comments do not pertain to the solvent based dips, or Formula-1.
After using all of these over the years, at one time or another, on my red fox traps, I have never seen evidence that the minute, natural odors from any of these dye sources has been detrimental at a fox set.
Now, if the "wax" put over dyed traps from any of these sources should become contaminated for any reason, without knowing it, that is a different scenario that may lead one to conclude that it was the trap "dye" that caused digging, or set avoidance by canines.
Just a humble contribution to the discussions on the this topic.
Basic Camera Gear: Canon EOS 50D with Canon EF 10-20mm, EF 28-135mm and EF 100-400mm lenses; Dutch Hill tripod with Wimberly Gimbal head.