RegX alpha Pattern won't process the letter 'H'

The function below analyzes free text and if the text contains a number followed immediately with a letter from A to M, it enters that value in the calling cell. But for some reason it won't extract "31H" from this text:

"BKK/MNL. 31H nad 22E inop, no sound. 4SR/NR"  (In fact it prevents "22E" from displaying as well)

It will display everyalphanumeric combo from 31A to 31M, but not 31H. The really curious thing is that if I change the word "nad" to any other word, then the H works. For example,

"BKK/MNL. 31H supercalifragilisticexpialidocious 22E inop, no sound. 4SR/NR"   does indeed produce  "31H, 22E" in the desired cell.

Is there anything in the fuinction that would explain that?

Thanks,

John :-)

Function GetSeats(InputCell As Range) As String   ' 'brettdj & Brad
    Dim RegEx, RegM, RegMC
    Dim MyDic
    Dim tmpStr As String
    Dim i As Long
 
    Set MyDic = CreateObject("scripting.dictionary")
    Set RegEx = CreateObject("vbscript.regexp")
    With RegEx
        '.Pattern = "ROW(S)? (\d+)-(\d+)"
        '.Pattern = "ROW(S)?\s*(\d+)\s*[,-/]\s*?(\d+)" 'Brad
        .Pattern = "ROW(S)?\s*(\d+)\s*([,-/|]|to|thru|through)\s*(\d+)"  'expanded Brad
        .Global = True
        .IgnoreCase = True
        If .test(InputCell.Value) Then
            Set RegMC = .Execute(InputCell)
            For Each RegM In RegMC
                If MyDic.exists(LCase$(RegM)) = False Then
                    For i = RegM.submatches(1) To RegM.submatches(3)
                        Select Case i
                        Case Is <= 4
                            tmpStr = tmpStr & i & "ACDF, "
                        Case Is < 7 > 4
                            tmpStr = tmpStr & i & "ABCDEF, "
                        Case Else
                            tmpStr = tmpStr & i & "ABCDEFHJK, "
                        End Select
                    Next
                    tmpStr = Left$(tmpStr, Len(tmpStr) - 2)
                    MyDic.Add LCase$(RegM), 1
                End If
            Next
        End If
        .Pattern = "\d+[A-M]+"
        If .test(InputCell.Value) Then
            Set RegMC = .Execute(InputCell)
            For Each RegM In RegMC
                If tmpStr = vbNullString Then
                    tmpStr = RegM
                Else
                    tmpStr = tmpStr & ", " & RegM
                End If
            Next
        End If
        GetSeats = tmpStr
    End With
End Function

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