None of these seem to have anything to do with umask values. Is there anything else I can check?

They don't have anything explicitly to do with umask, but the fact that they are different shows that something is changing the enviroment and that something could just as easily change the umask. Your task is to determine what that something is. Look through all the shell initialisation files both for your user and at the system-wide level. You will hopefully find whatever it is that is changing the umask there. Good luck.