Yeah don’t worry about that – the “add to my bag” and “great vault” rankings use a different approach than the other list rankings. You can read more here: The Great Vault Upgrade Finder Search
If you own an item we set it to zero and show it as “owned” for clarity. It might actually be a downgrade though were you to equip it. But many people found that display to be confusing. In this case you would need to go up to the 225 version or higher for the legendary to be an upgrade with the other gear currently in your bags.