Issue description:
Every time I put anything in the smeltery my game just crashes.
I tested it multiple times with different fuels, and different items, it crashes every time.

Crash report:
https://pastebin.com/WvTeicKh

Versions:

• Minecraft: 1.16.5
• Forge: 36.1.3
• Mantle: 1.16.5-1.6.72
• Tinkers Construct: 1.16.5-3.0.2.73

This issue is not covered on the roadmap or "What's new?"

Optifine is unsupported.