Setting the file. One moment.
Skill 104 · Resolving Ingestion Warnings
Subchapter 104.16
references/fixing-session-replay-warnings.mdMarkdown4 KBView on GitHub
These warnings come from the session replay ingestion pipeline — note the two message_* types don’t say “replay” in their names, but they are replay warnings (category ).
The symptom side is recordings that never appear or play back with gaps: each dropped message is a chunk of a recording, so a session can exist but miss segments.
replay| Type | Severity | What happened |
|---|---|---|
replay_lib_version_too_old | info | Recording sent by posthog-js 1.x below 1.75 — still processed, but the SDK is too old to support all recording features. Debounced per version |
message_contained_no_valid_rrweb_events | warning | A snapshot message carried no usable rrweb events — that chunk was dropped |
message_timestamp_diff_too_large | warning | A snapshot message’s event timestamps are 7+ days away from now — that chunk was dropped |
posthog:execute-sql: SELECT timestamp, details FROM system.ingestion_warnings WHERE type IN ('replay_lib_version_too_old', 'message_contained_no_valid_rrweb_events', 'message_timestamp_diff_too_large') AND timestamp > now() - INTERVAL 7 DAY ORDER BY timestamp DESC LIMIT 20 (narrow to a single type to isolate one variant). For message_timestamp_diff_too_large the details JSON carries startDiffDays/endDiffDays vs the 7-day threshold — the magnitude tells the story (8 days = buffering/late flush; hundreds/negative-looking = a broken client clock).$lib_version on the affected sessions’ events, via posthog:execute-sql): replay_lib_version_too_old names the outdated version outright in its details, and the other two also concentrate on old or unusual SDK versions when the payload shape is the problem.message_contained_no_valid_rrweb_events, look between the SDK and PostHog: a rewriting reverse proxy, compression/decompression middleware, or a custom transport that truncates or re-serializes the snapshot payload is the usual cause when the SDK is current.replay_lib_version_too_old): upgrade to a current version — 1.75 is the floor for full recording support, but go to latest; recording pipelines evolve quickly. Hunt pinned snippets so every page ships the same version.no_valid_rrweb_events): let replay traffic reach PostHog unmodified — remove or fix payload-rewriting proxies and custom transports; upgrade the SDK if it predates the current snapshot format.Record a fresh session on the affected app/platform, re-query system.ingestion_warnings with posthog:execute-sql (filter type IN ('replay_lib_version_too_old', 'message_contained_no_valid_rrweb_events', 'message_timestamp_diff_too_large'), timestamp after your fix) — no new occurrences — and confirm the new recording appears (posthog:query-session-recordings-list) and plays back complete, without gaps.