Is there any reason why an account would get stopped at 'System Validation' when the Process Definit

I am using access policies and role based membership to assign accounts to users.  But the accounts are being stopped at the System Validation stage and i can't figure out why. The users are added to the roles via membership rules, and the access policies then assign the access, but when the account is provisioning it is stopped at System Validation.

The Process Definition has the Auto Save Form checkbox checked, and if i manually assign the role, the account doesn't stop at that stage.  I don't see any odd exceptions in the logs or anything that would imply an error is occuring, so I am at a loss as to how to fix the issue.