query_settings_index_hints_tests.js module is used as a part of PQS tests passthrough and it checks if plans with and without query settings match.

However, there is a javascript issue in this line:

https://github.com/mongodb/mongo/blob/e1e9419b175b9dc770d508d1525fcdb0dda71725/jstests/libs/query/query_settings_index_hints_tests.js#L494

     const {winningPlanWithoutQuerySettings, rejectedPlansWithoutQuerySettings} =
            getAllQueryPlans(explainWithoutQuerySettings); 

getAllQueryPlans() returns an object {winningPlan, rejectedPlans}, not a tuple, so when JS unwraps it into winningPlanWithoutQuerySettings and rejectedPlansWithoutQuerySettings, they end up just `undefined` and equal, so they always pass any further equality checks.

This bug was introduced in SERVER-98924,

Another thing is that we can't just blindly fix this: if a plan contains "$$NOW", than in explain it will be unwrapped in {$const: <current date>}, which won't be equal between explains, as it will be updated to every time we run explain.