That's seems to be the case

Take a look at the initial shellite extraction from the LexTek which uses acetic acid

Clearly not as yellow as the phosphoric result; different bark was used however which could contribute to the effect (although both were using acacia obtusifolia - the phosphoric tests are done on a far older specimen)

Conversely, the second A/B really helped in removing the yellow pigment (however we're yet to see whether that's a good thing or not). Nonetheless, the double A/B is no doubt an effective purification technique, but one has to wonder if the salt to freebase to salt to freebase could carry with it some unwanted reactions. Perhaps a sample of both final products should be sent for some kind of component analysis