Hi Andrew,
> Additionally, here's the Info Summary App that it's in (remember this one works fine): ArcGIS Web Application
When I attempt to open your app, the app loads, but no data appears:
Tried to view in both Chrome and Firefox. Got the same result.
> here's the AGO hosted Feature Service URL:
https://services1.arcgis.com/pHowtmQeJXPeoWID/ArcGIS/rest/services/Norco_Valve_Activity/FeatureServe...
and Layer: Valve_Activities (ID: 3)
I was able to add both services to a new web map in the AGOL Map Viewer. I tried both layers with the Info Summary widget in a Web AppBuilder app. The Norco Valve Activity layer worked fine, but the Corona Query Valve layer was unresponsive.
I suspect it's probably a security accessibility issue with the Corona Query Valve layer from your ArcGIS Server site.
> so opened a tech support ticket
That's good - I am sure they can help resolve.
Hope this helps,