Your Active Directory is not replication or takes a while to replicate.
This is by design when you have bridegehead servers and a distributed AD
To force Active Directory to replicate the information to its domain controllers, you have a few possibilities. Do not forget that this might cause some overhead and bandwidth problems during peak hours!
You can use the Active Directory Sites And Services to force a replication. (check replication topology)
Active Directory Replication Monitor. You start Replmon and add the domain controllers to the list. Now you select syncronize each directory partition with all servers.
You can also execute Repadmin/syncall lubby.int where "lubby.int" is the domain to syncronize.
About the Author
Wim Peeters is electronics engineer with an additional master in IT and over 30 years of experience including time spent in support, development, consulting, training and database administration. Wim has worked with SQL Server since version 6.5. He has developed in C/C++, Java and C# on Windows and Linux in different European countries and different European languages. He writes knowledge base articles to solve IT problems and publishes them on the Lubby Knowledge Platform where he is one of the most important contributors and the main developer.