AWS DMS - Cloud formation - YAML - Migration task not moving from Ready to Starting/Load after instance launch

HI, I am able to create the DMS instance (Postgress to S3 migration) through the YAML file[full-load-and-cdc]. It is successfully creating Replication instance, Source and Target end points and migration task. But problem is that Replication task is in 'Ready' state post execution of YAML and not moving into next state like 'Starting' or 'Load complete, replication ongoing'. Noticed no errors. It works well if i use start/resume option on the AWS Console manually. Is any element in YAML script is missing to start the process automatically once the task gets created?

Note: TargetTablePrepMode is set to DO_NOTHING.

First migration job is created manually and second one which I'm working is created by Cloud Formation template.

What is equivalent YAML element [action shown in UI] to move the migration task into Starting state ?Below one is option in the console

 TableMappings: !Sub |
      {
      "rules": [
          {
              "rule-type": "selection",
              "rule-id": "132271480",
              "rule-name": "132271480",
              "object-locator": {
                  "schema-name": "${TableMappingSchemaNameFirst}",
                  "table-name": "%"
              },
              "rule-action": "include",
              "filters": [],
              "isAutoSegmentationChecked": false
          },
          {
              "rule-type": "selection",
              "rule-id": "132241247",
              "rule-name": "132241247",
              "object-locator": {
                  "schema-name": "${TableMappingSchemaNameSecond}",
                  "table-name": "%"
              },
              "rule-action": "include",
              "filters": [],
              "isAutoSegmentationChecked": false
          }]
        }

  TargetEndpointArn: !Ref TargetDBEndpoint
  ReplicationTaskSettings: !Sub |
      {
      "StreamBufferSettings": {
          "StreamBufferCount": 3,
          "CtrlStreamBufferSizeInMB": 5,
          "StreamBufferSizeInMB": ${TaskStreamBufferSizeInMB}
      },
      "ErrorBehavior": {
          "FailOnNoTablesCaptured": true,
          "ApplyErrorUpdatePolicy": "LOG_ERROR",
          "FailOnTransactionConsistencyBreached": false,
          "RecoverableErrorThrottlingMax": 1800,
          "DataErrorEscalationPolicy": "SUSPEND_TABLE",
          "ApplyErrorEscalationCount": 0,
          "RecoverableErrorStopRetryAfterThrottlingMax": true,
          "RecoverableErrorThrottling": true,
          "ApplyErrorFailOnTruncationDdl": false,
          "DataTruncationErrorPolicy": "LOG_ERROR",
          "ApplyErrorInsertPolicy": "LOG_ERROR",
          "EventErrorPolicy": "IGNORE",
          "ApplyErrorEscalationPolicy": "LOG_ERROR",
          "RecoverableErrorCount": -1,
          "DataErrorEscalationCount": 0,
          "TableErrorEscalationPolicy": "STOP_TASK",
          "RecoverableErrorInterval": 5,
          "ApplyErrorDeletePolicy": "IGNORE_RECORD",
          "TableErrorEscalationCount": 0,
          "FullLoadIgnoreConflicts": true,
          "DataErrorPolicy": "LOG_ERROR",
          "TableErrorPolicy": "SUSPEND_TABLE"
      },
      "TTSettings": {
          "EnableTT": false
      },
      "FullLoadSettings": {
          "CommitRate": 10000,
          "StopTaskCachedChangesApplied": false,
          "StopTaskCachedChangesNotApplied": false,
          "MaxFullLoadSubTasks": 8,
          "TransactionConsistencyTimeout": 600,
          "CreatePkAfterFullLoad": false,
          "TargetTablePrepMode": "DO_NOTHING"
      },
      "Logging": {
          "EnableLogging": true,
          "EnableLogContext": true,
          "LogComponents": [
              {
                  "Id": "SOURCE_UNLOAD",
                  "Severity": "LOGGER_SEVERITY_DEFAULT"
              },
              {
                  "Id": "SOURCE_CAPTURE",
                  "Severity": "LOGGER_SEVERITY_DEFAULT"
              },
              {
                  "Id": "TARGET_LOAD",
                  "Severity": "LOGGER_SEVERITY_DEFAULT"
              },
              {
                  "Id": "TARGET_APPLY",
                  "Severity": "LOGGER_SEVERITY_DEFAULT"
              },
              {
                  "Id": "TASK_MANAGER",
                  "Severity": "LOGGER_SEVERITY_DEFAULT"
              }
          ],
      },

      "TargetMetadata": {
          "ParallelApplyBufferSize": 0,
          "ParallelApplyQueuesPerThread": 0,
          "ParallelApplyThreads": 0,
          "InlineLobMaxSize": 0,
          "ParallelLoadQueuesPerThread": 0,
          "SupportLobs": false,
          "LobChunkSize": 0,
          "TaskRecoveryTableEnabled": false,
          "ParallelLoadThreads": 0,
          "LobMaxSize": 0,
          "BatchApplyEnabled": false,
          "FullLobMode": false,
          "LimitedSizeLobMode": false,
          "LoadMaxFileSize": 0,
          "ParallelLoadBufferSize": 0
      },
      "ControlTablesSettings": {
          "historyTimeslotInMinutes": 5,
          "HistoryTimeslotInMinutes": 5,
          "StatusTableEnabled": false,
          "SuspendedTablesTableEnabled": false,
          "HistoryTableEnabled": false,
          "ControlSchema": "",
          "FullLoadExceptionTableEnabled": false
      },
      "FailTaskWhenCleanTaskResourceFailed": false,
      "ChangeProcessingTuning": {
          "StatementCacheSize": ${TaskStatementCacheSize},
          "CommitTimeout": 1,
          "BatchApplyPreserveTransaction": true,
          "BatchApplyTimeoutMin": 1,
          "BatchSplitSize": 0,
          "BatchApplyTimeoutMax": 30,
          "MinTransactionSize": ${TaskMinTransactionSize},
          "MemoryKeepTime": 60,
          "BatchApplyMemoryLimit": 500,
          "MemoryLimitTotal": ${TaskMemoryLimitTotal} 
      },
      "ChangeProcessingDdlHandlingPolicy": {
          "HandleSourceTableDropped": true,
          "HandleSourceTableTruncated": true,
          "HandleSourceTableAltered": true
      },}