I made a resource pack that displays all possible enchantment levels within vanilla minecraft (from 0 to 32767) as roman numerals, and it works well until it gets to levels over the byte limit.
Once it reaches 256, it gets stuck at 255
For example, if I had an item with protection 789, it would display only "Protection CCLV" (255)
I attached some images for demonstration as well as the resource pack so you can recreate the bug.