Lure is a fishing rod enchantment that decreases the wait time for a bite on the hook.
Lure increases the rate of something biting the player's hook while fishing. Specifically, it decreases the wait time for something to appear by 5 seconds per level. See Fishing for more information.
If commands are used to increase the enchantment level beyond 5, the wait timer does not start and fish do not bite.
Issues relating to "Lure" are maintained on the bug tracker. Report issues there.