How to group and pivot records exclude nulls

Anonymous 

Please check if this helps

See File attached as well for the steps

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlTSUTICYqVYHQgHiMwgHEMzEyDH0BwuCxFAVwBE5kqxsQA=", BinaryEncoding.Base64), Compression.Deflate)), 
    let _t = ((type text) meta [Serialized.Text = true]) in type table [tickets_id = _t, Author = _t, Assighnee = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"tickets_id", Int64.Type}, {"Author", Int64.Type}, {"Assighnee", Int64.Type}}),
    #"Grouped Rows" = Table.Group(#"Changed Type", {"tickets_id"}, 
    {{"Author", each List.First(List.RemoveNulls([Author]))},
    {"Assighnee", each Text.Combine(List.RemoveNulls(List.Transform([Assighnee],each Text.From(_))),",") }}),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Grouped Rows", "Assighnee", Splitter.SplitTextByDelimiter(",", QuoteStyle.Csv), {"Assighnee.1", "Assighnee.2"})
in
    #"Split Column by Delimiter"