Enchantment glint is lost on tools (and probably armour) when dropped in any way way

The enchantment glint is lost when enchanted items are dropped. It occurs when the player drops it, it was in a chest that was broken and when removed from item frames. It occurs with every tier of tools and weapons and also occurs on bows, enchantment books, elytras and fishing rods

You can duplicate this bug by simply enchanting an item and then dropping it.