What the primary record establishes

The WebSocket sends an order-book snapshot followed by deltas. Kalshi’s seq counts messages on a subscription. If a level starts with 80 contracts, then loses 70 and gains 10, the correct result is 20. Missing the reduction leaves an erroneous 90. Kalshi WebSocket order book documentation ↗

What the distinction changes

One subscription can cover several markets. A sequence gap does not identify which market the missing message described. Request fresh snapshots for all subscribed markets or unsubscribe, await confirmation and subscribe again.

What to check before drawing a conclusion

Apply each returned snapshot as a replacement for the affected local book. A repeated subscribe for an existing market does not by itself resynchronize it. Log when the gap was detected and when clean snapshots were received so downstream decisions can be reviewed.