Anonymous user gets roles granted to them

I am running a Drupal system with the roledelay module installed. The system has a custom role with the "post comments without approval" permission enabled. That way, a user account that signs up won't get the the ability to post comments until 1 hour has passed.

Well, for reasons unknown, the role delay module sometimes grants that role to the anonymous user, which lets anonymous users post comments freely. When I look at the users_roles table, this is what I see:

mysql> select * from users_roles;
+-----+-----+
| uid | rid |
+-----+-----+
| 0 | 1 |
| 0 | 4|
| 1 | 2 |
| 1 | 3 |
| 1 | 4 |
| 2 | 2 |
| 2 | 4 |
[snip]

The second row is the one that should not be there, as it gives the anonymous user access to my custom role. I can delete that row manually to prevent anonymous users from posting, but it comes back within a few hours.

I looked through my logs and found this logfile entry on 4 seperate occasions:

User added to user - posting access role. Stage one

Note the extra space following the word "User". That suggests that there should be a username in there that is not present.

Any suggestions on how to keep this happening would be appreciated. I have access to the database and can send the copies of certain MySQL tables upon request.

Thanks,

-- Doug