Using anvil to rename an item beyond its max character limit will dupe the item by shift-clicking.
And also when you glow an item that has lore, the lore will be gone.

Hello,
Thank you for reporting the bug! Unfortunately I'm very busy and I don't have much time for this, but I will try to fix it ASAP. Pull requests are welcome.

Later than what I wanted, but I just pushed the fix to the bug. Thank you very much @dotxzxc for the report. I will publish the new jar in Spigot and Bukkit in the following days.