Full solver hangs when removing an unused Crystal Oscillator recipe node

I've encountered an issue where the Full solver will calculate successfully only if I leave an apparently unused Crystal Oscillator recipe node connected.

The unused node appears to have zero production and doesn't contribute to the factory's calculated output. However, disconnecting either of its inputs or deleting the node causes Full to hang indefinitely.

Steps to reproduce

1. Open the attached working .sfmd model.

2. Locate the two Crystal Oscillator recipe nodes (Standard and Insulated).

   1. Nuclear Planner>Not Raw

3. Observe that one recipe is producing approximately 48.32 items/min, while the other has its output limited to 0.

4. Disconnect either input from the inactive recipe node, or delete that node entirely.

Expected behavior

The Full solver should calculate successfully regardless of whether an unused recipe node is present.

Removing a node with zero production should not prevent the remaining production network from being solved.

Actual behavior

• With both Crystal Oscillator recipes present and connected, Full completes.

• Disconnecting either input from the apparently inactive recipe causes Full to hang.

• Deleting the inactive recipe also causes Full to hang.

• Restoring the node and both input connections allows Full to calculate again.

Additional observations

• The issue appeared while changing from the standard Crystal Oscillator recipe to the Insulated Crystal Oscillator alternate.

• The model contains several legitimate production feedback loops.

• Quartz Purification supplies Quartz Crystals and Silica, with the Silica used for aluminum production to reduce Bauxite consumption.

• Earlier attempts to disconnect or rearrange parts of the silica network also caused Full to hang.

• I have found a workaround: keeping the inactive recipe node with both inputs connected.

I suspect the extra node or its connections are affecting the Full solver's optimization behavior, even though the node appears to have no production.

Attachments

• Working .sfmd model with the inactive recipe connected

• Screenshot showing the two recipe nodes and their calculated production

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