Media players displaying black in package builds

Hello,

I am working on a project that involves a number of video files being played through screen space and world space widgets. Recently, we started making package builds, and found that those widgets sometimes just display black. I’ve been unable to find consistent repro steps for this, but it’s not something I’ve noticed in the editor, it only arises in package builds. Has anyone run into an issue like this before, and/or have recommendations for how to fix or troubleshoot the issue further?

The video files are placed in the content folder and imported into the engine from there. All the video files follow one of two specs:
Length: 5-15 seconds
Extension: .mp4
Codec: H264
Frame Rate: 30fps
Dimensions: 1920X1080
Bitrate: 9-10 Mbps

Length: 5-15 seconds
Extension: .mp4
Codec: H264
Frame Rate: 30fps
Dimensions: 3840X2160
Bitrate: 10-11 Mbps

The widgets contain a material on an image component. The material is in the User Interface domain, contains a texture sample with the media texture (linked to the media player) plugged into final color, and with a texture Sampler Type of external. The media player is set up to Open Source and Play the File Media Source, on Construct of the widget.

Happy to give more specifics if there is anything else that might be useful in diagnosing the issue, thanks!