Don't use Cloudsmith Opencpn [plugin]-alpha repositories for PIM master, use [plugin]-prod!
If you do use [plugin]-alpha, the files will exist in the repository, perhaps beyond the Retention Days (usually set to 30 days) but at your next development cycle, when you push to the alpha repository again, the files will be removed and errors will occur in PIM master!
So the rule that should be followed is to always use the [plugin]-prod repository, unless you intent to update the plugin again in a short period of time (less than 30 days) and in that situation you can use the plugins "Beta" repository.