There is some strange behavior going on between Spawn, JER, and by extension JEI. Normally, when viewing JEI's uses/sources screens with JER installed, a number of extra tabs are available in addition to the JEI ones. When Spawn is installed, however, two of these tabs, Villager Trading and World Generation, go missing entirely. Not just from Spawn's items, from every single loaded item in the game, modded or not. I further tested this in a clean, fresh instance with only the latest versions of JEI, JER, and Spawn installed, on the latest available version of forge for 1.20.1, and it produced the same result. The logs seem to be saying something about Spawn's Ant Garden biome, perhaps it has something to do with this? Do let me know if you need any further information.
latest.log