404 response to interstitial manifest skips forward towards live edge

[YoTonyF]

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

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

N/A

What version of Shaka Player are you using?

4.16.13 and confirmed also on 4.16.14-main-26-gceb01dcd5

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?
Custom

If custom app, can you reproduce the issue using our demo app?
Yes

What browser and OS are you using?
Linux Mint, Google Chrome 144.0.7559.96 (Official Build) (64-bit)

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

What are the manifest and license server URIs?

URL will be emailed

What configuration are you using? What is the output of player.getNonDefaultConfiguration()?

Config as provided in Demo App, unmodified.

What did you do?

Play back a Live HLS stream containing EXT-X-DATERANGE interstitials whose manifests return 404

What did you expect to happen?
Player should treat the 404 as a failure per Pantos D.5 and assume resume offset of 0

What actually happened?

Call out for manifest returns 404, showing error in Demo app:
Unhandled rejection in promise: shaka.util.Error { "severity": 2, "category": 1, "code": 1001, "data": [ "interstitial_manifest_url_here", 404, "Empty break\n", { "content-length": "12" }, 0, "interstitial_manifest_url_here" ], "handled": false, "message": "Shaka Error NETWORK.BAD_HTTP_STATUS (interstitial_manifest_url_here,404,Empty break\n,[object Object],0,interstitial_manifest_url_here)", "stack": "Error: Shaka Error NETWORK.BAD_HTTP_STATUS (interstitial_manifest_url_here,404,Empty break\n,[object Object],0,interstitial_manifest_url_here)\n at new shaka.util.Error (https://shaka-project.github.io/shaka-player/lib/util/error.js:101:15)\n at shaka.net.HttpPluginUtils.makeResponse (https://shaka-project.github.io/shaka-player/lib/net/http_plugin_utils.js:54:13)\n at shaka.net.HttpFetchPlugin.request_ (https://shaka-project.github.io/shaka-player/lib/net/http_fetch_plugin.js:263:38)" }

When reaching the insertion point, Player skips forward by the advertised interstitial duration instead of continuing to play the original underlying content. This is unexpected and undesirable behaviour and also would push the playhead too close to the live edge.

Are you planning to send a PR to fix it?
No