SERVER-81327: Added check for initialSyncId mismatch, but I believe there's an issue with how we validate the initialSyncId. Currently, we only check if it exists in the resumeToken, and we only append it to the token if the node has completed an initial sync at least once. If the node hasn't gone through initial sync, we don't add initialSyncId to the resumeToken. As a result, even if the node goes through initial sync again later, we won’t detect a mismatch. I think we need to update the validation logic to handle this case correctly.