I think that would seem to make sense, since it will pull other things aswell as DMT. MHRB is pretty clean as is but there is stills some plant fats in it, so when used already theres probably some stuff left in it that didnt precipitate out. The change in colour must mean something else is still in there.
I had been using white spirit and i reused the white spirit for a 4th pull and it went from being clear to an orange colour, and precipitate a layer of something, dunno wot yet, need to dry it. but it didnt crystalise.