Root DFS and ntlm hardening

Hi all

Recently we have tried to harden our NTLM. After applying some settings the access to the root of our domain has become intermittent \\domain.co.uk but all the namespaces as well as symbol etc I der the root are working fine and can be navigated to without an issue. 

DCs have now been applied the same settings which are send LM and ntlm and use V2 if negotiated. The issue is intermitted as it it will work on a DC and then stop and then work again. 

Similar is on the end user devices. 

We have on prem DCs and all devices are in tuned and entra joined.

We are hybrid but we do not sync or write the devices to ad. 

Replication and DFS itself are healthy. 

Issue are some users who have AFS paths already mapped to their devices it fails to connect to them sometimes. But new mapping works. 

Any ideas or assistance will be appreciated.