Hey @DannyDoritos6969,
I'm sorry to say, this is not a bug. Your content is stored on the EA Account where it was initially unlocked, so changing that can cause you to lose certain progress and/or cosmetics.
This is outlined in the warning that must be accepted when going through the steps to unlink an account, but you can read a bit more information about that here as well: https://help.ea.com/en/help/account/unlink-gaming-accounts-from-ea-account/
Since this cannot be transferred from one account to another, I'm afraid the only way to recover that would be linking this back to original EA Account, sorry.