jstests/sharding/sessions_collection_auto_healing.js expects a mongos can write its in-memory logical sessions to the durable sessions collection after the collection is created by an earlier refresh run on the config server. As part of writing its sessions, the mongos first checks if the sessions collection exists by refreshing from the config server, which reads from config.collections with majority read concern and nearest read preference. This can fail to find a newly sharded collection if the read targets a stale secondary outside the majority that first committed the sharded collection.

To guarantee the mongos refresh discovers the newly sharded collection, the test should wait for the latest operation on the config server primary to become committed on all secondaries by calling rs.awaitLastOpCommitted() on the config server before triggering this refresh on the mongos.