Answer recommended by moderator
Oh, you were stacking subscriptions. That will explain it. This context is important.
You can only stack up to 5. See explanation from Microsoft here: https://support.microsoft.com/en-us/accounts-billing/subscriptions/what-happens-if-i-add-another-microsoft-365-for-home-subscription-to-my-account You will have to hang onto the codes and wait to redeem them.
