Forum Discussion
Office 365 Groups naming policy reaches public preview
https://support.office.com/en-us/article/office-365-groups-naming-policy-6ceca4d3-cad1-4532-9f0f-d469dfbbb552
AFAIK, the Azure AD naming policy doesn't take a custom attribute into account when it constructs names. This would be easy to do with PowerShell by updating the DisplayName attribute with whatever's in CustomAttribute14 after a group exists.
And it is safe to use the policy. All it's doing is making sure that the DisplayName attribute is correctly populated. You can do that yourself or let the policy do it.