RTBlintAlpha
Native layout was removed in Native Ads 1.1
The encoded native request still carries layout, which Native 1.1 replaced with plcmttype and context.
What it means
layout was a Native 1.0 field (feed, atomic, etc.). Native 1.1 dropped it in favour of plcmttype and context. It still appears on 1.2 payloads copied from old fixtures.
Why it matters
1.1+ parsers ignore layout. The placement type they actually read is missing, so the buyer guesses at in-feed vs recommendation widget.
How to fix it
If ver is 1.0, layout is still legal. On 1.1 or 1.2, drop layout and set plcmttype and context instead.
Example that trips it
{ "native": { "request": "{\"ver\":\"1.2\",\"layout\":1,\"assets\":[{\"id\":1,\"title\":{\"len\":90}}]}" } }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.