There's a little buglet in #85387 (which was the PR that closed #84046), specifically, it doesn't account for the possibility that there's both a default/request **and** and a final pipeline, and that they can both touch the `@timestamp` field.

`IngestService#postIngest` was added in #85387, and it's intended that the logic there only runs **once**, after all the pipelines associated with the request have been executed. But as it's currently written, the logic actually runs after each individual pipeline runs.

The consequence of that is that if there's a default/request and a final pipeline in use for a document, and the final pipeline changes the timestamp field, the `rawTimestamp` recorded for the `IndexRequest` associated with the document will mistakenly use the value it sees after the default/request pipeline runs, and **not** the most correct one (from after when the final pipeline runs).

/cc @martijnvg 
server/src/main/java/org/elasticsearch/ingest/IngestService.java
? String.format(
                            Locale.ROOT,
                            "the default pipeline for %s index(es) including [%s]",
                            defaultPipelineIndices.size(),
                            defaultPipelineIndices.stream().sorted().limit(3).collect(Collectors.joining(","))
                        )
                        : Strings.EMPTY,
                    defaultPipelineIndices.size() > 0 && finalPipelineIndices.size() > 0 ? " and " : Strings.EMPTY,
                    finalPipelineIndices.size() > 0
                        ? String.format(
                            Locale.ROOT,
                            "the final pipeline for %s index(es) including [%s]",
                            finalPipelineIndices.size(),
                            finalPipelineIndices.stream().sorted().limit(3).collect(Collectors.joining(","))
                        )
                        : Strings.EMPTY
                )
            );
        }
    }
    /**
     * @return pipeline configuration specified by id. If multiple ids or wildcards are specified multiple pipelines
     * may be returned
     */
    
    
    public static List<PipelineConfiguration> getPipelines(ClusterState clusterState, String... ids) {
        IngestMetadata ingestMetadata = clusterState.getMetadata().custom(IngestMetadata.TYPE);
        return innerGetPipelines(ingestMetadata, ids);
    }