The Feature Info widget does not display attachments or use the 'Attachments' Arcade expression in the pop-up if the data source is a hosted feature layer with a selected features view.

Solución alternativa

1. Add the layer to a web map and use the web map as the data source instead of the layer.
2. Display the attachments in the layer when used as the data source and the view is 'Selected features.'

Pasos para reproducir