Can't update Google Sheet Add-on
According to a comment on How do I update a Google Sheets Add-On, it could possibly be that there's a propagation time of 2-3 days for the changes/update to reflect to the servers.
Additionally, there's a comment to an answer on Google Sheet Add-on not updating and a community member have shared that it took 2 days for the update changes to reflect on their end. If you've followed precisely the guide from Update and manage your published add-on, then propagation time could most likely be the reason.