Collected over six months against a platform commerce API. This is not about one platform. Any write API with an approval workflow, partial-update support, and status-as-string produces the same shapes.
One sentence:
No response is proof of success. Only re-fetch is.
Why this chapter bites non-ASCII users
The APIs here are Korean marketplaces. Their status values, rejection reasons, and validation errors come back as Korean strings, not enum codes. Several entries below are about what happens when you match on those strings. If your API speaks English, substitute your own status vocabulary; the mechanism (prefix-sharing states, human-readable messages posing as machine values) is identical. The Korean strings are kept verbatim because they are the real data, each with a gloss.
Hit all five in one day, so it became a table.
Symptom
Three at once.
Symptom
One queue watching an approval workflow produced three of these in three days. Each is silent: no exception, no log line, and an item leaves observation.