[CI] MixedClusterClientYamlTestSuiteIT test {p0=search.vectors/160_knn_query_missing_params/kNN query in a bool clause - missing num_candidates} failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #5895 / 8.14.3_bwc
• elasticsearch-periodic #5895 / 8.13.4_bwc
• elasticsearch-periodic #5890 / 8.13.4_bwc

Reproduction Line:

./gradlew ":qa:mixed-cluster:v8.14.3#mixedClusterTest" -Dtests.class="org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT" -Dtests.method="test {p0=search.vectors/160_knn_query_missing_params/kNN query with missing num_candidates param - size provided}" -Dtests.seed=37E3771D909F6082 -Dtests.bwc=true -Dtests.locale=ti-Ethi-ET -Dtests.timezone=Europe/Nicosia -Druntime.java=23

Applicable branches:
8.x

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: Failure at [search.vectors/160_knn_query_missing_params:94]: expected [2xx] status code but api [search] returned [400 Bad Request] [{"error":{"root_cause":[{"type":"x_content_parse_exception","reason":"[1:67] [knn] unknown field [k]","stack_trace":"org.elasticsearch.ElasticsearchException$1: [1:67] [knn] unknown field [k]\n\tat [email protected]/org.elasticsearch.ElasticsearchException.guessRootCauses(ElasticsearchException.java:704)\n\tat [email protected]/org.elasticsearch.ElasticsearchException.generateFailureXContent(ElasticsearchException.java:632)\n\tat [email protected]/org.elasticsearch.rest.RestResponse.build(RestResponse.java:184)\n\tat [email protected]/org.elasticsearch.rest.RestResponse.<init>(RestResponse.java:143)\n\tat [email protected]/org.elasticsearch.rest.RestResponse.<init>(RestResponse.java:114)\n\tat [email protected]/org.elasticsearch.rest.RestControlle
[truncated]

Issue Reasons:

• [8.x] 2 consecutive failures in test test {p0=search.vectors/160_knn_query_missing_params/kNN query in a bool clause - missing num_candidates}
• [8.x] 2 consecutive failures in step 8.13.4_bwc
• [8.x] 3 failures in test test {p0=search.vectors/160_knn_query_missing_params/kNN query in a bool clause - missing num_candidates} (2.6% fail rate in 114 executions)
• [8.x] 2 failures in step 8.13.4_bwc (100.0% fail rate in 2 executions)
• [8.x] 2 failures in pipeline elasticsearch-periodic (100.0% fail rate in 2 executions)

Note:
This issue was created using new test triage automation. Please report issues or feedback to es-delivery.

[elasticsearchmachine]

Pinging @elastic/es-delivery (Team:Delivery)