Duplicate rows when expanding JSON list

List.Zip is your friend.

let
    Source = Json.Document("{
  ""result"": [
    {
      ""metricId"": ""HOST(\""windows.host\"")"",
      ""dataPointCountRatio"": 0.000303,
      ""dimensionCountRatio"": 0.00202,
      ""data"": [
        {
          ""dimensions"": [
            ""COMPUTER-ABC1234567""
          ],
          ""dimensionMap"": {
            ""dt.entity.host"": ""COMPUTER-ABC1234567""
          },
          ""timestamps"": [
            1723680000000,
            1723766400000,
            1723852800000,
            1723939200000,
            1724025600000,
            1724112000000,
            1724198400000,
            1724284800000,
            1724371200000,
            1724457600000,
            1724544000000,
            1724630400000,
            1724716800000,
            1724803200000,
            1724889600000,
            1724976000000,
            1725062400000,
            1725148800000,
            1725235200000,
            1725321600000,
            1725408000000,
            1725494400000,
            1725580800000,
            1725667200000,
            1725753600000,
            1725840000000,
            1725926400000,
            1726012800000,
            1726099200000,
            1726185600000,
            1726272000000
          ],
          ""values"": [
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            1512,
            803.25,
            null,
            null,
            null,
            null,
            null,
            null,
            740.25
          ]
        },
        {
          ""dimensions"": [
            ""COMPUTER-XYZ9876543""
          ],
          ""dimensionMap"": {
            ""dt.entity.host"": ""COMPUTER-XYZ9876543""
          },
          ""timestamps"": [
            1723680000000,
            1723766400000,
            1723852800000,
            1723939200000,
            1724025600000,
            1724112000000,
            1724198400000,
            1724284800000,
            1724371200000,
            1724457600000,
            1724544000000,
            1724630400000,
            1724716800000,
            1724803200000,
            1724889600000,
            1724976000000,
            1725062400000,
            1725148800000,
            1725235200000,
            1725321600000,
            1725408000000,
            1725494400000,
            1725580800000,
            1725667200000,
            1725753600000,
            1725840000000,
            1725926400000,
            1726012800000,
            1726099200000,
            1726185600000,
            1726272000000
          ],
          ""values"": [
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            744,
            713
          ]
        }
      ]
    }
  ]
}"),
    result = Source[result],
    result1 = result{0},
    data = result1[data],
    #"Converted to Table" = Table.FromList(data, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    #"Renamed Columns" = Table.RenameColumns(#"Converted to Table",{{"Column1", "Records"}}),
    #"Expanded Records" = Table.ExpandRecordColumn(#"Renamed Columns", "Records", {"dimensions", "timestamps", "values"}, {"dimensions", "timestamps", "values"}),
    #"Extracted Values" = Table.TransformColumns(#"Expanded Records", {"dimensions", each Text.Combine(List.Transform(_, Text.From)), type text}),
    #"Added Custom" = Table.AddColumn(#"Extracted Values", "Custom", each List.Zip({[timestamps],[values]})),
    #"Removed Other Columns" = Table.SelectColumns(#"Added Custom",{"dimensions", "Custom"}),
    #"Expanded Custom" = Table.ExpandListColumn(#"Removed Other Columns", "Custom"),
    #"Extracted Values1" = Table.TransformColumns(#"Expanded Custom", {"Custom", each Text.Combine(List.Transform(_, Text.From), "|"), type text}),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Extracted Values1", "Custom", Splitter.SplitTextByEachDelimiter({"|"}, QuoteStyle.Csv, false), {"timestamp", "value"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"timestamp", Int64.Type}, {"value", type number}}),
    #"Replaced Value" = Table.ReplaceValue(#"Changed Type",each [timestamp],each #datetime(1970,1,1,0,0,0) + #duration(0,0,0,[timestamp]/1000),Replacer.ReplaceValue,{"timestamp"}),
    #"Changed Type1" = Table.TransformColumnTypes(#"Replaced Value",{{"timestamp", type datetime}})
in
    #"Changed Type1"

How to use this code: Create a new Blank Query. Click on "Advanced Editor". Replace the code in the window with the code provided here. Click "Done". Once you examined the code, replace the Source step with your own source.