Thank you for reaching out!
When you upgrade, all devices associated with the same account get upgraded. You don’t have to pay by device!
Could you try one thing for me? Tap on UPGRADE again, and then the three-dot menu on the upper right. You will see a dialogue popping up that says “restore purchase.” Tap on it and see if the upgrade can be applied properly.
If this doesn’t work, please send me an email with your receipt (support @ my-alfred.com). I will look into it for you!
Thanks in advance!