Symptoms
When running the configuration for the 'Execute Get Attachments List' method of the 'When the view executed initialize' rule even though the Input Property 'List Item ID' is required the field populates blank. Making no changes, canceling out of everything and running the form we get the following error:
SmartObject property ID is a required property for selected method GetAttachmentsList. Value must be set.
Diagnoses
This is a bug being investigated further.
Resolution
Disabling the 'Execute Get Attachments List' method action will clear up the error and doesn't seem to impact another aspect of the form's performance.