Users being assigned the Administrator ID

I have created a template page for users to view their profile from the front end in a read only style. At the top of the template, I am specifying the user id in this manner:

<?php $user_ID = get_current_user_id(); ?>

This works perfectly most of the time. The problem occurs once in a while, with no apparent patter, that the user will see the Administrator profile instead of their own. Then when they log off and log on again, they will see their own profile. This completely baffles me. I even deleted the original Administrator account and created a new one.

Any thoughts or help in this matter would be appreciated.

Regards,

Bob