I am presuming its an error, so for me this is the closest I can get to a quick work around.
1)Store morph target of subtool requiring colour.
2)Select Project all with RGB on(ensuring your model is closely overlapping the one that that has the texture you wish to extract)
3)Revert to original morph target.
You can use blur with just rgb on if you need to soften the edges of your texture before additional edge work, or use a mask around the edges when originally extracting.