ContentTweaker fluids seem to be unusable in crafting recipes, at least when using createTwekaer, so long as ther is also any other fluid in the recipe. for example <recipeType:create:mixing>.addRecipe("icing_mixing", "heated", <fluid:minecraft:lava> * 20, [<item:minecraft:white_wool> * 2], [<fluid:minecraft:milk> * 20, <fluid:contenttweaker:molten_sugar> * 20], 20); will not craft properly

I'm unable to reproduce.

Here are my scripts:

content.zs

#loader contenttweaker
import mods.contenttweaker.fluid.FluidBuilder;

new FluidBuilder(true, 0xff0000).build("generic_fluid");

recipes.zs

<recipetype:create:mixing>.addRecipe("mixing_test_3", "none", <item:minecraft:arrow>, [<item:minecraft:glass>, <item:minecraft:dirt>], [<fluid:minecraft:milk> * 20, <fluid:contenttweaker:generic_fluid> * 20]);

<recipeType:create:mixing>.addRecipe("icing_mixing", "heated", <fluid:minecraft:lava> * 20, [<item:minecraft:white_wool> * 2], [<fluid:minecraft:milk> * 20, <fluid:contenttweaker:generic_fluid> * 20], 20);

Both of those recipes are working just fine.

Make sure you are heating the basin correctly?