login.def is present but empty. My thought process could be faulty, but the user logins that are sporadically failing have user ID's that match the ID's assigned to machine accounts - see excerpt from passwd file:
Note how the UID's are 593, 594 and then jump to 1205, 1206, etc.? The machine account comsw05 also has uses 1207 and the user sjohnson/UID 1207 is the most recent user to encounter the failed login problem. I neglected to mention in my original post that the "permanent" resolution I've come up with is to add a machine account line similar to what you see for comsw05 with a UID that matches the actual user profile for that specific machine. For example, in the passwd file I've added the line:
which ended the problem from occurring for user atallon/UID 1206.
Maybe I have more then one problem on my hands and can't see it because I am unfamiliar with the O/S.....