This result was identified while diagnosing a performance issue on Atlas. 

{find: projectDocument filter: {_and: \\\{opportunities.orderInfo.orderNumber: {_exists: true _ne: null}}, \\\{opportunities.orderInfo.cwOrderId: {_exists: false}}} _db: rhdo-gallery-project-service-staging _clusterTime: {clusterTime: {_timestamp: {t: 1645959584 i: 2}} signature: {hash: {_binary: {base64: WK0oU7yTsO1sL5k3qTq5y4OnZrM= subType: 0}} keyId: 7005939129837945000}} lsid: {id: {_uuid: 0c6daeb3-bbe5-4be5-99e3-93cbf21c6563}}} planSummary: IXSCAN
Unknown macro: { opportunities.orderInfo.cwOrderId}
keysExamined: 111623 docsExamined: 109506 cursorExhausted: true numYields: 4993 nreturned: 23 queryHash: 274C58B8 planCacheKey: 1A09723E reslen: 985644 locks: {ReplicationStateTransition: {acquireCount: {w: 4994}} Global: {acquireCount: {r: 4994}} Database: {acquireCount: {r: 4994}} Collection: {acquireCount: {r: 4994}} Mutex:
Unknown macro: {acquireCount}
}} storage: {data: {bytesRead: -1890016436 timeReadingMicros: 158488225}}protocol: op_msg durationMillis: 159718

The server was behaving normally, albeit with fairly degraded performance due to the workload. This entry was identified while reviewing the logs for potential index optimizations.