HLS/DASH manifest drift
on a primetime live lane.

GET /live/event/manifest.m3u8 HTTP/1.1
host: cdn.example.com
accept: application/vnd.apple.mpegurl

----- cycle 0 (T+0m, before snapshot+reread) -----
HTTP/2 200
content-type: application/vnd.apple.mpegurl
server-timing: manifest-fetch;dur=22
x-cdn: cdn-A/fra02
x-packager: pkg-prime-04

#EXTM3U
#EXT-X-VERSION:6
#EXT-X-TARGETDURATION:6
#EXT-X-MEDIA-SEQUENCE:41879     ← jumped from 41871 over a 2s window (8-step drift, baseline 0)
#EXT-X-MAP:URI="init.mp4"
#EXTINF:6.000,
041879.ts
#EXTINF:6.000,
041880.ts
#EXTINF:6.000,
041881.ts
#EXTINF:6.000,
041882.ts                    ← starts with #EXT-X-DISCONTINUITY (out-of-window)
#EXT-X-DISCONTINUITY
#EXTINF:6.000,
041883.ts

# ext_x_daterange_coverage_vs_upstream:    0.0   (upstream had 4 cues in this window)
# ext_x_media_sequence_drift_s:            1.93  (segment numbering jumped in 1.93s)
# ext_x_discontinuity_in_window:           true  (out-of-window discontinuity tag on 041882)
# cohort impact over 90s window:
#   cohort_hls_parse_fail_ratio:            0.118
#   cohort_player_startup_stall_ratio:      0.107 (within baseline 0.011)
#   encoder.bitrate_target_delta_pct:       0.30  (within baseline)
#   cdn.availability:                       pass  (edge serving manifest green)

----- cycle 1 (T+0m +3s, after snapshot+reread + packager split) -----
HTTP/2 200
content-type: application/vnd.apple.mpegurl
server-timing: manifest-fetch;dur=24
x-cdn: cdn-A/fra02
x-packager: pkg-prime-reissue-01

#EXTM3U
#EXT-X-VERSION:6
#EXT-X-TARGETDURATION:6
#EXT-X-MEDIA-SEQUENCE:41881     ← reads continuous from prior window
#EXT-X-MAP:URI="init.mp4"
#EXTINF:6.000,
041881.ts
#EXTINF:6.000,
041882.ts                    ← no discontinuity tag, presentation continues
#EXTINF:6.000,
041883.ts

# ext_x_daterange_coverage_vs_upstream:    1.0   (cue points restored)
# ext_x_media_sequence_drift_s:            0.12  (within baseline; packager reads continuous)
# ext_x_discontinuity_in_window:           false (no out-of-window tag injected)
# rebalance_hints emitted:                  snapshot_manifest_reread_from_clean_source,
#                                          repackage_title_with_clean_window_anchor,
#                                          reissue_packager_split_for_affected_lane

{
  "stream_id": "cklivemanifestdriftprimetime8821",
  "source": "https://cdn.example.com/live/event/manifest.m3u8",
  "protocol": "HLS",
  "checked_at": "2026-08-09T19:14:37Z",
  "ranked_hypotheses": [
    {
      "rank": 1,
      "hypothesis": "manifest_packager_segment_drift",
      "confidence": 0.89,
      "evidence_signals": [
        "manifest.ext_x_media_sequence_drift_s → fail (1.93s jump, baseline 0; 8-step segment-numbering desync over 2s window)",
        "manifest.ext_x_daterange_coverage_vs_upstream → fail (0.0 vs 1.0 baseline, 4 cues dropped across the stitch seam)",
        "manifest.ext_x_discontinuity_in_window → fail (out-of-window discontinuity tag on segment 041882)",
        "cohort.cohort_hls_parse_fail_ratio → fail (0.118 vs 0.015 baseline over 90s window)",
        "cohort.cohort_player_startup_stall_ratio → fail (0.107 vs 0.011 baseline over 90s window)",
        "encoder.bitrate_target_delta_pct → pass (0.30 within baseline; encoder healthy)",
        "cdn.availability → pass (manifest served green on the same cohort/CDN)"
      ]
    },
    {
      "rank": 2,
      "hypothesis": "discontinuity_injection_stitcher",
      "confidence": 0.06,
      "evidence_signals": [
        "discontinuity tag present but co-occurs with segment-numbering drift and cueless coverage on the same cohort — pattern matches a broader packager drift, not a stitcher-only discontinuity bug"
      ]
    },
    {
      "rank": 3,
      "hypothesis": "vod_manifest_dropping_cues",
      "confidence": 0.05,
      "evidence_signals": [
        "this is a live HLS lane not a stitched-VOD lane; SCTE-35 postmortem covers the VOD stitcher cue-filter case explicitly — pattern does not match (no cdn-A→cdn-E seam, no vod.cue_point_coverage probe involvement)"
      ]
    }
  ],
  "agent_rebalance_hints": [
    "snapshot_manifest_reread_from_clean_source",
    "repackage_title_with_clean_window_anchor",
    "reissue_packager_split_for_affected_lane"
  ],
  "surfaced_to_humans": [
    {"owner": "packager vendor",     "task": "engage on mid-window EXT-X-MEDIA-SEQUENCE anchor model"},
    {"owner": "on-call",             "task": "page for the manifest-drift root-cause review"},
    {"owner": "reliability team",    "task": "assign the postmortem write-up"}
  ]
}