There are very commonly low-level enchantments, even when on Level 30. These include Unbreaking I, Sharpness II, and Efficiency III. Even if there is a higher enchantment, such as Unbreaking III, it is likely it will be single and not include any others. Please fix this bug quickly, maybe in a 1.14.3. release or something. I'm saying this because it has a huge impact on gameplay. It also happens nearly all the time, such as 9 out of ten enchantments being low-level and/or single.