1.21Neoforge, Modern-Industrialization2.2.16, Kubejs2100.7.0build.119
game：

file path:

I am unable to identify any errors
js:
MIMachineEvents.registerMachines(event => {
event.craftingSingleBlock(
// English name, internal name, recipe type (see above), list of tiers (can be bronze/steel/electric)
"Autoclave", "autoclave", AUTOCLAVE, ["electric"],
// Background height (or -1 for default value), progress bar, efficiency bar, energy bar
186, event.progressBar(95, 45, "arrow"), event.efficiencyBar(48, 86), event.energyBar(4, 4),
// Number of slots: item inputs, item outputs, fluid inputs, fluid outputs
2, 2, 2, 2,
// Capacity for fluid slots
16,
// Slot positions: items and fluids.
items => items.addSlots(39, 35, 2, 1).addSlots(107, 35, 2, 1),
fluids => fluids.addSlots(39, 55, 2 , 1).addSlots(107, 55, 2, 1),
// front overlay?, top overlay?, side overlay?
true, true, true
);
})

You need to enable runtime datagen to produce the required model files.

OK, I can successfully use runtime datagen in 1.19.2, but in 1.21, it dose not work.

Keep in mind that the JSON format changed between 1.19.2 and 1.21. This might explain why the latter doesn't work?