HLS + cbcs w/ Widevine playback fails without error

[Trevor-Uplynk]

Have you read the FAQ and checked for duplicate open issues?
yep

If the problem is related to FairPlay, have you read the tutorial?
unrelated to FairPlay

What version of Shaka Player are you using?
Tested with the demo player, which was v4.15.5 at this writing.
Also tested in a couple of the "best" older version of the demo player:

• v4.14.21
• v4.13.25
• v4.12.18
• v4.11.21
• v4.10.26

This stream actually plays successfully in v4.9.36, so I didn't test any version older than that.

Can you reproduce the issue with our latest release version?
Yes

Can you reproduce the issue with the latest code from main?
Yes

Are you using the demo app or your own custom app?
Demo app

If custom app, can you reproduce the issue using our demo app?
n/a

What browser and OS are you using?
Chrome Version 138.0.7204.49 (Official Build) (x86_64)
MacOS Ventura 13.4

For embedded devices (smart TVs, etc.), what model and firmware version are you using?
n/a

What are the manifest and license server URIs?
Manifest: https://content.uplynk.com/channel/e4bd472a0f1440748fb19a143de6246e.m3u8?expand=drm_wv_l3
License Server: https://content.uplynk.com/wv

What configuration are you using? What is the output of player.getNonDefaultConfiguration()?
This command fails when executing in the console of the demo player page. Have added no additional configuration beyond manifest URL and license server URL.

What did you do?
Attempt to play the stream in the demo player.

What did you expect to happen?
Stream plays

What actually happened?

1. HLS manifest is requested and returned (observable in browser dev tools network panel)
2. HLS media playlist for video variant is requested and returned
3. HLS media playlist for audio variant is requested and returned
4. Init segments and media segments are requested and returned
5. Widevine license is requested and returned
6. Player "loading" spinner disappears, but default poster image remains.
7. Media playlists for both audio and video continue to be re-requested and returned
8. Media segments continue to be requested and returned
9. Playback never begins.
10. No errors are displayed in the console.

Interestingly, if I provide a master manifest which lists exactly one video variant + the audio variant, playback succeeds. Example of such a manifest URL: https://content.uplynk.com/channel/e4bd472a0f1440748fb19a143de6246e.m3u8?expand=drm_wv_l3&rays=e

Are you planning to send a PR to fix it?
I'm afraid I am unsure where to start a contribution here. I would be happy to provide one given some guidance.