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Title

One-line summary

The prompt

Help me debug this issue using an explicit reasoning trail, so I can follow and check your logic instead of trusting a guess.

Symptom: [WHAT HAPPENS, INCLUDING EXACT ERROR MESSAGES OR WRONG OUTPUT]
Expected: [WHAT SHOULD HAPPEN]
When it started / what changed recently: [RECENT CHANGES, OR "UNKNOWN"]
Environment: [LANGUAGE/RUNTIME VERSIONS, OS, RELEVANT DEPENDENCIES]
Code and logs: [PASTE THE RELEVANT CODE AND ANY STACK TRACE OR LOG OUTPUT]

Work in this loop, and show each step:
1. Observations: list only facts established by the material above. No interpretation yet.
2. Hypotheses: enumerate at least three distinct causes consistent with all observations. For each, state what current evidence supports it and what evidence would rule it out.
3. Ranking: order the hypotheses by likelihood and say why — based on this evidence, not on which bug is most common in general.
4. Next probe: give me the single cheapest test that best separates the top hypotheses — a specific log line to add, value to print, input to try, or command to run. State the expected result under each hypothesis, so the outcome is informative either way.

I will run the probe and reply with the result. When you update your ranking, say explicitly which hypothesis was weakened or eliminated and why. Do not propose a fix until one hypothesis explains every observation, including the timing of when the bug appeared. If my reported result contradicts your leading hypothesis, treat the report as correct and revise.

Write it so someone can paste it straight into Claude, ChatGPT or Gemini and fill the [BRACKETS].