According to Amazon this is not a problem to fix. The incomplete listings do not have any effect and are not a risk for performance notifications. They are visible because this is how Amazon USED TO display feeds for incomplete listings. When Market Web Services was used to get information about potential FBA shipments i.e. shipment "plans".
In newer Amazon accounts (those created in 2012 or later), you can only see these incomplete listings by going to reports and generating an FBA inventory report, that's why for anyone who started selling in the last 5 years this is not noticed as an issue. In older Amazon accounts, they show up in manage inventory as incomplete listings and are visible. Again, as it turns out this is not even a 'bug' or a 'problem' to fix.
However, it is annoying for some users to have to look at these incomplete listings: for those users they should archive those listings if that works to get them out of sight or simply disable this feature.
To disable: to not see these listings please turn off the FBA and slow moving restriction alerts.