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Impressed by how quickly a post on Academia SE was correctly flagged as spam, I looked at the timeline for Academia post 142860 (10k on Academia required) — it was deleted 58 seconds after posting, very good:
The screenshot shows that the question was asked 2020-01-14 11:34:36Z, and got deleted and locked by Community♦ at 2020-01-14 11:35:34Z... twice.
How did it get locked and deleted twice? Did it get twelve rather than the required six spam flags, or is there some other reason?
This was caused by a race condition. Two users happened to cast a sixth spam flag on the post at exactly the same time, which caused the system to process all the resulting actions twice for the post because neither process knew anything about the other process already running.
