I have a web map that uses Arcade expressions in popups in 3 separate layers to highlight certain data fields, but then adds a Field List (new Map Viewer) to each layer's popup to display the complete data record for each event.
These records show data in both map viewers, and in the Basic web app that I'm using for testing. However, when the map or the app are embedded into a 3rd-party website, those data records are blank. The field names appear, but not the associated data.
I cannot find mention of a similar situation here. Any ideas?