Industrial Foregoing Version: industrialforegoing-1.12.2-1.11.2-212
TeslaCoreLib Version: tesla-core-lib-1.12.2-1.0.15

The enchantment sorter considers an enchanted book with one enchantment as an enchanted item.

The enchantment extractor does not consider an enchanted book with one enchantment as an enchanted item.

So an enchanted book with one enchantment that gets classified as an enchanted item and gets sent to an enchantment extractor to be processed ends up in conveyor belt limbo for the rest of eternity.

So there are two options that I can see here:

A. The enchantment sorter does not consider an enchanted book with one enchantment as an enchanted item.

B. The enchantment extractor accepts an enchanted book with one enchantment as input and simply moves it to an "Enchanted Book Output" slot.

Option A will result in some enchanted books with one enchantment separated from other enchanted books in the final result.

Option B will result in all enchanted books with one enchantment end up together in the enchnment extractor output.

Option B seems like a good idea.