Versions:

• Polymorph: 1.16.5-0.30
• Forge: 36.2.9

Observed Behavior:

The auto-smelting upgrade for Sophisticated Backpacks does not work with Polymorph installed (see: P3pp3rF1y/SophisticatedBackpacks#300). The items enter the correct slots but do not start smelting.

Expected Behavior:

Fuel is expended to smelt the objects in the upper slot.

Steps to Reproduce:

1. Install Sophisticated Backpacks (sophisticatedbackpacks-1.16.5-3.11.1.390.jar) and Polymorph (polymorph-forge-1.16.5-0.30.jar) under Forge 36.2.9
2. Add a smelting upgrade to the pack and add a smeltable object + fuel

Does this happen with the Smelting upgrade too or just the Auto-Smelting upgrade?

Only the auto-smelter, it turns out. The un-upgraded version works as expected.