Hello,
What are you basing the unsuspended information on? The suspended "yes" in the list users page.. or right on the "show user data" page? I ask because there is a cache used for the large list of users that might not be be updating.
If the suspended page through apache returns to normal, then more investigation would be required. Check your /var/log/directadmin/error.log errortaskq.log and system.log to see if you can find anything related to the unuspension.
Also, check /usr/local/directadmin/data/users/username/user.conf. See what the "account=ON" status is. When you tell DA to suspend the account, the account will be set to OFF to let DA know not to unsuspend the account during the monthly reset.
John