# MULTIPLE_VARIANT_CONFLICT

- Surface: API
- HTTP status: 409
- Details: `{ experimentId: string, runId: string, idType: string, targetingKeyHash: string }`

## Cause

One Entity was observed under more than one Variant in the same Run, so it is bucketed to `__multiple__` and its contribution is untrusted.

## Fix

This is a data-integrity signal, not a transient failure. It usually means the Targeting Key changed identity mid-Run, or two clients evaluated the same subject under different keys. Results that include the affected Entity are not safe to decide on: correct the Targeting Key and start a new Run.

## Related

- [TARGETING_KEY_MISMATCH](https://splitch.dev/docs/error/TARGETING_KEY_MISMATCH)
- [RUN_FROZEN](https://splitch.dev/docs/error/RUN_FROZEN)

Source: https://splitch.dev/docs/error/MULTIPLE_VARIANT_CONFLICT