On BGP protocol level, the loop check is on the receiving side - received paths are scanned for local ASN. The transit may not send you your routes with your A

On BGP protocol level, the loop check is on the receiving side - received paths are scanned for local ASN. The transit may not send you your routes with your ASN due to how its policies are configured, but that is configurable, not protocol-level issue. And most BGP implementations have knobs to disable the loop check, so on your side you could just disable it.