Moving tools were used in order to move subscriptions to a new service node, however PPA moving tool could not reconfigure the DNS zone for domains with a new IP address.
There is a failed task in PPA:
Multiple errors during NS update: Destination host 'old.dns.servicenode' (#5), IP '126.96.36.199' : Unable to establish connection with the node #5.
DNS resource already contain new DNS servers, but the zones for problem domains are still having an old one in name servers list.
Service template for the problem domains contain a custom DNS servers list:
Products > Service Templates > template_name > Parameters > Nameservers
Set default name server for the service template, and apply the template changes to all susbcriptions (Products > Service Templates > template_name > Apply Template Limits and Parameters)