Custom blocks with item overrides do not appear in the correct furnace recipe book category. They appear in the “Items” category instead of the “Blocks” category.

Demonstration

The attached screenshots demo the bug. The hovered items’ names explain whether they have an item override or not. Note that the item backed by a block is in the wrong category.

Reproduction

The demo screenshots and code are taken from the behavior pack in the attached world for convenience. This world can be opened (in Minecraft Preview) for inspection or unzipped to access the code associated with such. Note that testing this in a separate world requires the Furnace Recipe Book experiment.