Using ArcGIS Maps SDK for JavaScript 5.0.9 arcgis-popup component
Popup configured in AGOL webmap displaying image media from publicly accessible url.

The image url contains braces { } anything between these including the braces is being removed from the url.

Resulting in an empty div with dimensions displaying in the popup.

This doesn't occur when using the now deprecated "@ArcGIS/core/widgets/Popup.js"

The quick solution is to remove braces from the image filenames, however thought I'd mention this here, it appears to be a bug.