Expected behavior

I am inside of syncRecordsToCloudKit function of SyncEngine class. Inside the completion block called modifyRecordsCompletionBlock of modifyOpe, chunkItUp function is used to request less than 400 operations on a single request:

            let chunkedRecords = recordsToStore.chunkItUp(by: 300)
            print("CHUNKING BY: \(chunkNumber)")

            for chunk in chunkedRecords {
            print("chunk: \(chunk.count)")
                self.syncRecordsToCloudKit(recordsToStore: chunk, recordIDsToDelete: recordIDsToDelete, completion: completion)
            }

This should sync data 300 ops at a time without a problem.

Actual behavior(optional)

However, I get an error message as if I went over 400 operations per request:

ErrorHandler.Chunk: Limit Exceeded: the request to the server is too large.CKError.Code: 27

output:
CHUNKING BY: 300
chunk: 300
chunk: 300
chunk: 157

This problem results in not even single data being synced to the iCloud. How do we bypass this problem?