We have implemented a Grid Repeat Layout with Master-Detail row editing in expandable rows. We have configured a post-action activity to run in the flow action that is configured in the row operation. In running the tracer, we see that the post-action activity is being run when the user clicks the Save button, when the user clicks the Discard button, and when the user expands a different row. Also in the tracer, I see that there isn't anything in the parameter page that would indicate the action the user took.
I then looked at the sample in the UI Gallery. It does not have a post-action activity configured, so I did a private checkout of the flow action and added a call to an activity. I see the same behavior; the activity seems to be invoked on the same 3 triggers: Save button, Discard button, expand a different row.
Is there a way to determine what action the user took, or do I need to open an SR for a product fix?