When executing IO mappings it may occur, that a variable that is supposed to be mapped to the outer scope is not available.

In most cases, it is fine to throw an error. However, there are scenarios in which this should be expected and handled instead of throwing an exception.

One use case is the handling of RPA tasks. We can not determine which variables will be returned from the RPA vendor. In those cases, the user should enable a configuration flag that skips all output mappings on external tasks.