1.17.1
Fabric
Latest version of Polymorph

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[20:15:11] [main/WARN]: Method overwrite conflict for getMatchingStacks in polymorph.mixins.json:AccessorIngredient, previously written by net.id.incubus_core.mixin.IngredientMixin. Skipping method.

I changed this mixin in Polymorph 0.15-1.17.1+ so this should be fixed now.