Problem

When a user attempts to assign a job to a user who is already assigned to the same task workflow step, the assignment fails with an error as expected. However, the system acquires a task lock before performing this validation check and does not release it when the error occurs.

As a result, the task remains locked, preventing other users and system processes from making modifications to the task until the lock expires or the process ends.

Solution

• Move the duplicate assignment check inside the protected try ... catch block in CreateUserJobOperation::assignJob so that any validation failure properly releases the task lock before returning the error.
• Ensure the task lock is released cleanly under all exception scenarios.

Acceptance Criteria

•   Attempting to assign a duplicate user job returns the appropriate error and immediately releases the task lock.

•   Subsequent operations on the task are not blocked after an assignment failure.