Sessions expire ahead of schedule
A session/token store (Cassandra with per-row TTLs) starts logging users out early and dropping short-lived grant tokens before they should expire, beginning ~03:30. Dashboards: error rate flat, but 'session expired' events jumped and a few cache layers show entries vanishing ahead of their TTL. Context: one of three new Cassandra nodes added last night came up with NTP not yet synced and its clock is ~7 minutes *ahead*. How do you triage, stop the premature data expiry, and recover affected users?
What a strong answer looks like
Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.
0:00 of about 35 min
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.