@Liang.Xue,

There are 2 possible causes for what appears to be a duplicate result:

1. Your request does not retrieve all possible content field names. There is probably at least 1 or maybe more fields that are not part of your request but that have changed between 18:15 and 22:08 on that day. If that is the case then you will see what appears to be duplicate records.
2. It could also be that a specific alert was published twice.

To verify this hypothesis I made the same request as you, but limited the date range to 26-27 March 2019, and retrieving all possible content field names. I then identified and compared those 2 records. The following fields all changed content:

Body Size, Created Date, Item Count N - Same Feed, Item ID, Linked Count N - Same Feed, Linked Id Prv N - Same Feed, Novelty Timestamp, Related RICs, Story Date Time, Take Date Time, Total Sentences, Total Words, Update Size

This shows these records are not duplicates.

That said, your query is very much data related. This forum is aimed at software developers using Refinitiv APIs. The moderators on this forum do not have the deep expertise in all the content sets available through our products required to answer your question. I advise you to call the Refinitiv Helpdesk number in your country. They will either have the answer for you right away, or will reach out to the content experts who can provide the answer you're looking for.

PS: here is the request body I used for my test:

{
  "ExtractionRequest": {
    "@odata.type": "#ThomsonReuters.Dss.Api.Extractions.ExtractionRequests.NewsAnalyticsExtractionRequest",
    "ContentFieldNames":
      ["Asset ID", "Asset Store Version", "Attribution", "Author", "Body Size", "Broker Action", "Broker Action Code", "CIN Code", "Common Code", "Created Date", "Cross Reference", "CUSIP", "Engine Version", "Event Type Code", "Exchange Code", "Exchange Description", "Feed ID", "File Code", "First Mention", "Fitch Issuer ID", "Headline", "Headline SubType", "Headline SubType Code", "Instrument ID", "Instrument ID Type", "Is Breaking", "ISIN", "Issue PermID", "Issuer OrgID", "Issuer PermID", "Item Count 1 - Same Feed", "Item Count 2 - Same Feed", "Item Count 3 - Same Feed", "Item Count 4 - Same Feed", "Item Count 5 - Same Feed", "Item Genre", "Item ID", "Item Type", "Language", "Linked Count 1 - Same Feed", "Linked Count 2 - Same Feed", "Linked Count 3 - Same Feed", "Linked Count 4 - Same Feed", "Linked Count 5 - Same Feed", "Linked Id Last 1 - Same Feed", "Linked Id Last 2 - Same Feed", "Linked Id Last 3 - Same Feed", "Linked Id Last 4 - Same Feed", "Linked Id Last 5 - Same Feed", "Linked Id Prv 1 - Same Feed", "Linked Id Prv 2 - Same Feed", "Linked Id Prv 3 - Same Feed", "Linked Id Prv 4 - Same Feed", "Linked Id Prv 5 - Same Feed", "Market Commentary", "Market Commentary Code", "Metadata", "Moodys Issuer ID", "More News", "Named Items", "News Source", "Novelty Timestamp", "Number of Companies", "OPOL", "PE Code", "PILC", "PNAC", "Product Permission", "Products", "Quote ID", "Quote PermID", "RCP ID", "Reference", "Related RICs", "Relevance", "Reuters Editorial RIC", "RIC", "S&P Issuer ID", "SEDOL", "Sentiment", "Sentiment - Negative", "Sentiment - Neutral", "Sentiment - Positive", "Sentiment Bearing", "Sentiment Words", "SICC", "Stock RIC", "Story Body", "Story Date Time", "Story Type Code", "Take Date Time", "Take Sequence Number", "Ticker", "Topics", "Total Sentences", "Total Words", "TRBC Activity Code", "TRBC Activity Code Description", "TRBC Business Sector Code", "TRBC Business Sector Code Description", "TRBC Economic Sector Code", "TRBC Economic Sector Code Description", "TRBC Industry Code", "TRBC Industry Code Description", "TRBC Industry Group Code", "TRBC Industry Group Code Description", "Update Size", "User Defined Identifier", "User Defined Identifier2", "User Defined Identifier3", "User Defined Identifier4", "User Defined Identifier5", "User Defined Identifier6", "Valoren", "Wertpapier" ],
    "IdentifierList": {
      "@odata.type": "#ThomsonReuters.Dss.Api.Extractions.ExtractionRequests.InstrumentIdentifierList", 
      "InstrumentIdentifiers": [
      { "Identifier": "AAPL.O", "IdentifierType": "Ric" }
      ],
      "ValidationOptions": {"AllowHistoricalInstruments": true},
      "UseUserPreferencesForValidationOptions": false
    },
    "Condition": {
      "ReportDateRange": "Range",
      "QueryStartDate": "2019-03-26",
      "QueryEndDate": "2019-03-27",
      "NewsAnalyticsRelevanceOperator": "GreaterThanOrEqualTo",
      "NewsRelevanceValue": 0.5,
      "NewsAnalyticsPrevailingSentiment": "Positive",
      "NewsAnalyticsNovelty": "Novelty7Day",
      "NewsFilterNoveltyOperator": "GreaterThanOrEqualTo",
      "NewsNoveltyValue": 10,
      "NewsTopicsCodes":[ "CMPNY", "TECH" ],
      "IncludeImbalace": true,
      "NewsAnalyticsSource": "ArticlesAndAlerts",
      "NewsItemsSource":"Selected",
      "NewsAttributionsCodes": [ "RTRS", "BSW" ]
    }
  }
}

THanks, Christiaan!

Good to have your support here, after the training webex last week hosted by Richard.