name: problem-fix-verify
Produce an answer in a fixed, always-identical format when there is a problem to explain and fix. In plain terms: say what's broken, how you fix it, how you know it's fixed. Works for any topic, not just code.
Open with one sentence saying where the problem is. Then three bullets, in this order. No intro, no closing, no repeats.
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The Content-Type problem sits inside RM-011: it's the first row of the known-defects table.
application/json somewhere. That's why a value like text/plain; x=application/json also passes.;, strip spaces, and compare it to application/json case-insensitively. When RM-006 arrives, application/merge-patch+json will be accepted too.text/plain; x=application/json must return 415, while application/json; charset=utf-8 must keep working.