With low porosity hair, I think it's possible for just about anything to "build up." For me, it's polyquats and, recently hypothesized, too much gelatin (I can use some in my okra gel, but the gelatin PT is just too much.)
I don't know the ingredients for all your products, so can't really tell you.
3a (Corkicelli), highlighted, fine, low porosity
modified CG, since April '07
CG since 3/11/08
HGs: Anything Sevi; Curly Kinks Satin Roots, Curlycue ReNew and Coil Jam; homemade FSG and okra gel; soap bars; UFD Curly Magic; Botanical Spirits Jellies, CJ Repair Me