Cached sellers.json is not usable
The cached sellers.json for this hop exists but cannot be read as a sellers.json document.
What it means
sellers/<asi>/sellers.json was present in the cache but is not a JSON object with a sellers array, so sid was not checked against it.
Why it matters
A corrupt or HTML error-page cached as sellers.json is not a lookup. The hop stays unverifiable until the file is a real sellers.json document.
How to fix it
Replace the cached file with the document published at https://<asi>/sellers.json. Confirm it parses as JSON and contains a sellers array.
Example that trips it
rtblint validate --resolve --cache ./supply-cache request.json
Fires when sellers/<asi>/sellers.json exists but is not a sellers.json object.
Check your payload
Paste a bid request or response into the tester to see whether this code fires against it, or gate on the id in CI with the CLI: the id is stable, wording is not.
Back to the full diagnostic code reference.