Umai pepperoni 40% Loss in weight.Case hardened

[Jim]

Slight case hardening is quite common. I would say that fermenting for only 24 hours was likely not enough to drop the PH and if the PH is high, case hardening and “collapsing”/wrinkling – irregular shape you describe is one of the consequences. Meat substitution could have made the sausage more lean, but wouldn’t contribute much to case hardening.