I have what I thought would be a simple PowerApps App that collects a few pieces of information and uploads this to SharePoint. I found that since I am including a picture from the camera control I needed to do this with a Flow. The date fields were being passed to the run command from a DatePicker using DatePicker.SelectedDate. For the Flow, I tried to use:
formatDateTime(triggerBody()['Updatefileproperties_ReportDate'],'MM-dd-yyyy')
in the expression field but I ended up with the following error in PowerApps:

Then I decided to hard code the date as string and use variables in the flow to take a string date and convert to Date. then add the Date to the File Properties Update. The flow now contains:


This produces the exact same error from PowerApps. To make matters worse, when I look at the 28 day run history, none of my attempts show up. There are only two entries and both are from tests I performed, not from the manual action from PowerApps. So I have 2 questions:
1. how can I pass the DatePicker.SelectedDate to the Flow to end up in a Date column in SharePoint?
2. Why am I not seeing the Flows fail? In fact, no matter what change I make in PowerApps or in Flow, the error message I get is exactly the same. This seems very strange to me.
Bonus points for anyone that can tell me how to update only a subset of fields when creating this record as some fields in SharePoint are not required and will be modified later by users directly in SharePoint.