ldap_fastest_host_selection.js configures a MongoDB server with LDAP connection pooling which connects to several LDAP proxy servers. All but one proxy introduces extreme amounts of latency into requests. Sometimes, the test fails because it requests connection pool statistics, but observes that some proxies are missing.
This is expected behaviour, as the per-host connection pools can be shut down if they are inactive for too long. We should make the test tolerate missing entries, so long as the low latency host is included in the results.