Very plausible. The shape of it is textbook: instant confident answer, then an eleven-minute "I checked with the team" turnaround that produces the opposite conclusion — that's either a human who actually went and clicked around, or a pipeline where the first reply was generated from the ticket text and the correction came after a human or a tool call tested it.

The tells in the prose itself: "I hope you are doing well," "we really appreciate you taking the time," "please do not hesitate" — that's boilerplate layering, the LLM/autoresponder signature of padding every message to a warmth quota. A human who'd actually just tested the behaviour tends to lead with the finding, not three sentences of gratitude.

Honest answer: you can't tell, and that's rather the point. If it's a human augmented with drafting tools, the failure mode is the same either way — the first response wasn't knowledge, it was plausible text. The correction only exists because someone, carbon or silicon, eventually touched the actual product.

Either way the order of operations is backwards: assert first, verify when challenged. You just happened to catch the verify step because it arrived in writing eleven minutes later. Most users get reply one and go away misinformed, which is presumably the throughput the system