PDF Embed API Issue: Modern Viewer Not Rendering Correctly

Hi Adobe Team,

We're currently experiencing several issues with the PDF Embed API.

We're using both Lightbox Embed Mode and Sized Container Embed Mode. In addition to the issues already reported in other community posts, such as:

• Feature config can't be set

• Connecting to ...printHelper_main...js.map violates CSP

we're also seeing another issue where the viewer is not rendering correctly across multiple embed modes, with UI controls missing. For example, in Sized Container Embed Mode, only the scrollbar is visible while the viewer controls and content are missing.

The viewers are also not displaying as shown in the Modern Viewer documentation:
https://developer.adobe.com/document-services/docs/overview/pdf-embed-api/modernviewer

This is affecting our production environment, and we'd really appreciate it if the team could investigate.

Is there anything we can provide to help speed up the investigation and resolution?

Thank you,
Jenn