RTBlintAlpha
Native asset id is used more than once
Two native request assets share the same id, so a response cannot map assets unambiguously.
What it means
Asset ids must be unique within the Native Markup Request. Two assets with the same id leave the buyer guessing which slot a response asset fills.
Why it matters
The response is allowed one object per request id. A duplicate id is a collision; most buyers take the first and ignore the rest, or drop the impression.
How to fix it
Number assets uniquely (1, 2, 3, …). Do not reuse an id for a second title or image.
Example that trips it
{ "native": { "request": "{\"ver\":\"1.2\",\"assets\":[{\"id\":1,\"title\":{\"len\":90}},{\"id\":1,\"data\":{\"type\":2}}]}" } }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.