Computer Configuration > Windows Settings > Security Settings > Local Policies > Security Options > Interactive Logon: Number of Previous logons to cache value 4
After the following policy was set, did you login the user on the machine with the with the connection to DCs?
If not, the user will not be able to cache the credentials.
We have to logon the user with connected to the DCs to cache the credentials, then if disconnected with the domain, the cached credentials will be used.
If i misunderstand you, feel free to let me know.