Checked for existing issues

• I have checked for existing issues, and have found none.

Tested latest version

• I have checked that this occurs on the latest version.

GregTech CEu Version

7.1.0 ee0cf6a

Minecraft Version

1.21.1 NeoForge

Recipe Viewer Installed

None

Environment

Singleplayer

Cross-Mod Interaction

No

Other Installed Mods

None

Expected Behavior

The items in the input bus are consumed one after the other

Actual Behavior

The Multi Smelter idles, as if no / an invalid recipe were input.
Sometimes, it consumes the input without producing anything.
If an item is input via pipe, it starts working again.

Steps to Reproduce

1. Build a multi smelter.
   The energy tier, coil and tier of bus used is irrelevant, as long as the input hatch has multiple slots (LV+above).
2. Supply it with energy as needed
3. Insert multiple items into the input bus manually.
   This can be done by dragging with the middle mouse button while having a stack of a smeltable item (e.g. iron ore) picked up, or by drag-clicking with a stack in survival/creative.
4. Alternatively, switch to alloy smelter mode, and insert two stacks of the same item using the same method (e.g. 1 stack of tin ingots, 2 stacks of copper)

Additional Information

Something similar occasionally happens with EBFs. I cannot reproduce that, but know that it happened at least twice.