Those are the latest old-servers from a particular batch in use and are blocking sending them back.
Purchased hosts labsdb1009/10/11 intended as a replacement are in full production, and available to be used instead. Because the improved architecture (allowing real high availability, load balancing and automatic failover) there, however, is a (conscientious) decision of not covering all use cases -in particular, direct(?) write of user databases T156869- so the migration may not be 100% transparent and user impacting (some programming changes may be needed). In all other areas, however, the now hosts are more powerful, better managed and with better data quality.
Cloud team should probably setup a roadmap to understand when the decommission can happen; otherwise, rather than a decommission process, we will have an unplanned outage -current hosts are failing component by component, have multiple hw/IPMI alerts, their storage is not redundant disk-wise (due to disk space constraints, which it is still a growing issue), and in general it is unlikely they will survive more than a few months.