What was your scent? I have had that happen with 2 soaps, one where I used a tea tree oil from Trader Joes that wasnt an essential oil, and one where I used an odd fragrance oil. Mind you, they were more like 65% lard, but they looked exactly like that - orange and sticky.
All of my other lard soaps are fine even a year or more out. But the lard I use does have BHT or something in it for sure. I always blamed the failures on the scents, but I suppose I could have gotten a bad batch of lard...
The FO I used is (ironically) Bramble Berry Fresh Snow from their "clear and vanilla-free" list. FO presumably would affect any oil, but there is a distinct pattern of DOS experiences with lard. It happens to some and not to others, but I think there may be something going on there.
I have a few thoughts based on lard being a variable product, but I'm open to ideas.
(1) Lard could vary a lot in composition depending on breed, diet, environment, area of the body and who knows what else. Some lards could have a lot more linoleic acid than others.
(2) Industry usually inoculates lard with a tiny bit of a stabilizer cocktail that was researched and adopted decades ago. It is composed of BHA, propyl gallate and citric acid (for chelation). Whether a lard product is stabilized could make a big difference.
(3) The rendering process is important. To whatever extent non-fat material from the animal remains in the product (especially iron-containing material, but even moisture), it could be a lot less stable.
(4) I have noticed some lard is firm (like what I used to get in 50 lb cubes from SC) and some lard is soft and runny. I guess the difference is probably based on whether it has been hydrogenated. Hydrogenation would produce a more stable product.
I figure if you get on the bad side of one or more of these factors, it could cause problems.
Despite the artisanal appeal, the lard I used could be on the wrong side of multiple factors. Maybe composition of the lard, definitely stabilization and hydrogenation, and maybe the rendering technique.