I could not find the mentioned global name anywhere else in the mod so I replaced it with "new_recipe" thus fixing the loading issue for me.

4.155 Loading mod reverse-factory 9.0.40 (data-updates.lua)
4.162 Error ModManager.cpp:1764: Failed to load mod "reverse-factory": reverse-factory/func.lua:458: attempt to index global 'solid_into_fluid_recipe' (a nil value)
stack traceback:
reverse-factory/func.lua:458: in function 'makeFluidRecipe'
reverse-factory/func.lua:414: in function 'makeFluidItem'
reverse-factory/prototypes/solid-fluids.lua:43: in main chunk
[C]: in function 'require'
reverse-factory/data-updates.lua:2: in main chunk
4.204 Loading mod core 0.0.0 (data.lua)
4.311 Checksum for core: 3810281447
4.327 Error ModManager.cpp:1764: Error in assignID: recipe-category with name 'recycling' does not exist.

Good catch, I pasted that line of code from my other mod (since they share a lot of similar code), though I'm not sure why I didn't run into this error during my own testing. Fixed in v9.0.41