Windows 2003 Scheduled Tasks fail to start after a few days

I've been searching all day for a solution for this, and so far have come up with nothing.

I have some scheduled tasks on a server that run PowerShell scripts. They run fine for a day or so, and then suddenly stop. The error they start giving is:

0x80070569: Logon failure: the user has not been granted the requested logon type at this computer. Verify that the task's Run-as name and password are valid and try again.

Simply reseting the password for the Run as user fixes the problem. Everything I've seen online claims that this is a problem with permissions, but I don't believe that as the tasks run fine for a day. The user account being used is a domain account with administrator privileges.

Problem solved. If you guessed it was policies, you win a cookie.

Simply put, entering the username and password for the run as user in a task adds that user to the local run as batch policy. The catch is that when group policies are updated, this is overwritten. The problem is alleviated by reentering the password (thus adding the user to the local policy again) until the next time policies are pulled.

It's a silly mistake on my part, but I figured I'd post the answer here for anyone else who may be suffering from the same dilemma.