Explanation
When the activity encounters a NullReferenceException, the Finally block is not executed and a runtime error occurs. This is because the Catches section of the Try Catch activity only handles the ArgumentException type, which is a specific type of exception that occurs when one of the arguments provided to a method is not valid1. A NullReferenceException is a different type of exception that occurs when there is an attempt to dereference a null object reference2. Since the Catches section does not have a handler for the NullReferenceException type, the exception is not caught and the execution is stopped with a runtime error. The Finally block, which contains the activities that are always executed regardless of the outcome of the Try Catch activity, is also skipped3. References: ArgumentException Class, NullReferenceException Class, and Try Catch from UiPath documentation.