Technology:remove_prereq nullifies prerequisites value of Technology if there's no values left in it.
I believe Factorio expects it to be at least empty table. I'm not sure, though, but boblibrary's bobmods.lib.tech.replace_prerequisite expects it's value to be not nil. So, either your mod or his has bug.
Technology:remove_prereq nullifies prerequisites value of Technology if there's no values left in it. I believe Factorio expects it to be at least empty table. I'm not sure, though, but boblibrary's bobmods.lib.tech.replace_prerequisite expects it's value to be not nil. So, either your mod or his has bug.