Network drives are not all there on boot

I’m currently running WinNT servers with logon script to map drives for each user. All users have same script with limited access to each. Intermitently a user boots a machine, logs on, and can only see 1 or 2 of the network drives instead of the total 7 or 8. I’ve discovered a temporary fix in which I log them out, log in as admin with mapping, log out admin, log user back in. All the servers on my domain are carrying the script so it’s not just a matter of one server being overloaded or anything. Any suggestions?