I think you may have found an issue with Process Manager and Sugar combined. We check for deleted = 0 for the user being related to the team, but we do not check for user = deleted from the user table.
I will fix Process Manager for checking for users = deleted from users table, but can you open the Global Team and see if this User is still showing up?
Send me your email address to email@example.com and I will send you the patch for Process Manager.
Please include what version of Sugar you are using, Sugar CE, SuiteCRM or Sugar ON Demand.