It is possible, since they have a third-party integration, that they could be experiencing a SQL Deadlock. If that is what is happening, the user would receive the 'File in use by another task' error message. We have experienced this issue before with another client where ScanForce and Starship were both installed and one of the applications was locking the record while the other was attempting to update. You can determine what is going on by running a SQL trace profiler or watch the process monitor in SQL Management Studio, when the event happens (assuming it can be duplicated on demand/consistently).