Could it be tracing fast due to the total percentage or composition of the unsaponifiables? Lard is very low in unsaponifiables. I’ve seen <0.2% and < 0.8% (
source), while unrefined shea butter can have as much as 15-16% (
source;
source Table 2). Avocado oil has 4-9% unsaponifiables (
source), but some other edible oils have very low percentages (
source).
In Susan Cavitch’s book The Soap Maker’s Companion, she says this on page 108:
“The percentage of unsaponifiables is very high in pomace olive oil... The unsaponifiables in pomace create a thick, waxy, synergistic soup, making the oils more viscous, quick to react, and fast to pull the neutral oils into the soapmaking reaction. They act as a catalyst, getting the reaction going, and building up some momentum.”
I have been using unrefined shea at nearly 40% in one of my recipes and it wants to trace pretty fast. When I switched to refined shea instead of unrefined shea, the recipe slowed down noticeably. The first time I made soap with 3% orange wax, I barely got it into the mold. It has a composition similar to lanolin (
source) and is high in unsaponifiables. According to Jan Berry, lanolin can speed trace (
source), but I haven’t used it, so I don’t know from experience.
ETA: I also found this
post by an SMF member that gives a good explanation of how and why the structure of a fatty acid affects speed of trace.