The MongoDB connector initiated a full historical re-sync without explanation.
To prevent this from happening, contact your DBA to set your Mongo Oplog Retention Period to between 24 hours and 7 days, as per our Mongo DB Setup Guide.
When oplog retention is set to lower than the recommended value of 24 hours, it is more likely we lose the location of the sync progress.
If this occurs, the connector will automatically re-sync to recover. No action is needed.