Loot Table's "enchant_with_levels" function not working

I made a loot table for a chest and when I added armor, tools and enchanted books I made them be enchanted with levels. The armor and tools pick a number between 10 and 100 and enchant it with that many levels and the enchanted books pick a number between 20 and 200. However for some reason most of the time I just get an enchanted book with no enchantments.