When I first saw the raisin and juniper bags last fall they felt kind of waxy to me and I mentioned it to my SA who agreed. I think it is just the thickness of the leather and the process that they go through. I have noticed that the Apple conditioner softens the legacy leather a bit so that might be something to try?
My white Ali had a sticky waxy feel on the underside of the strap when I first got it. After conditioning it with Apple conditioner its gone. It was an Ebay purchase so who knows what/why . . .
It could be a waxy/silicone of some kind. I just learned that the tanning process for leathers involves the application of colored urethanes, the smooth dark brown or black edge of the leathers is also a colored urethane (which can peel off), in short are breatheable, flexible plastic . . . perhaps if there is a glitch in the process it feels different, and maybe that's why some bags seem to gather transfer easier?!? another question for the experts!