In jstests/with_mongot/e2e/hybridSearch/score_fusion_failure_assertions.js, this line

TestData.pinToSingleMongos = true; 

was added as it appeared to resolve NamespaceNotFound errors that consistently appeared locally (when the test was run with the vector_search_extension_enabled_single_shard suite). These errors are not hit when the test is run with mongot_e2e_single_shard suite.

However, it's clear now that the added line did not fix the behavior as the test has exhibited flaky behavior on evg (failing every so often with the same NamespaceNotFound error) and so it should be removed and we should look into a different fix for this error. 

Note that in an earlier investigation it appeared that inserting docs into the collection appeared to resolve the errors locally but, for the purposes of the test, would be unnecessary. The assertions in score_fusion_failure_assertions.js should be able to work on an empty collection.