TopologyTimeTicker::onNewLocallyCommittedTopologyTimeAvailable is called from three different places:

• ConfigServerOpObserver::onInserts
• ConfigServerOpObserver::onUpdate
• VectorClockMongoD::onConsistentDataAvailable

ConfigServerOpObserver::onInserts avoids calling onNewLocallyCommittedTopologyTimeAvailable during initial sync. However, ConfigServerOpObserver::onUpdate does not.

Because of that, when a node undergoes initial sync, it could be that onUpdate registers a topology time tick with a commit time CT.
If that happens to also be the stopTimestamp of the initial sync, then VectorClockMongoD::onConsistentDataAvailable will be called with commit time also CT. This violates this invariant, as commitTime will be equal to _topologyTimeByLocalCommitTime.crbegin()->first, so the configsvr replica undergoing initial sync will crash.