Add logic to the target_info metric generation in the OTLP endpoint, so that any samples with the same timestamp for the same (target_info) series are de-duplicated. It comes out of a user's bug report about duplicated target_info samples in Grafana Mimir (which uses the Prometheus target_info generation logic).
If I'm not mistaken, duplicate target_info samples should stem from multiple resources in the same OTLP request being translated to the same target_info label set. It shouldn't be caused by a Prometheus bug.