Userform selection yields wrong information

So your problem is using a non-unique value for your search. I made a few changes. Your listbox did not specify the width for the last column, so I set it to 80, and added another 0 width column.

ColumnWidth property for lstLookup now reads: 100 pt;60 pt;40 pt;80 pt;70 pt;80 pt;0 pt
Then I added one line to your search button code:

                If rngFind.Row > 1 Then
                    lstLookup.AddItem rngFind.Value
                    lstLookup.List(lstLookup.ListCount - 1, 1) = rngFind.Offset(0, 1)
                    lstLookup.List(lstLookup.ListCount - 1, 2) = rngFind.Offset(0, 8)
                    lstLookup.List(lstLookup.ListCount - 1, 3) = rngFind.Offset(0, 2)
                    lstLookup.List(lstLookup.ListCount - 1, 4) = rngFind.Offset(0, 4)
                    lstLookup.List(lstLookup.ListCount - 1, 5) = rngFind.Offset(0, 7)
                    lstLookup.List(lstLookup.ListCount - 1, 6) = rngFind.Row
                End If

This means that now you have the row number of the search results available to do your textbox updating. Which requires a change to the double-click event for your listbox (changed it as little as possible):

Private Sub lstLookup_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
'declare the variables
    Dim cPayroll As Integer
    Dim i As Integer
    Dim findvalue
    'error block
    On Error GoTo errHandler:
    'get the select value from the listbox
    For i = 0 To lstLookup.ListCount - 1
        If lstLookup.Selected(i) = True Then
            cPayroll = lstLookup.List(i, 6)
        End If
    Next i
    'find the payroll number
    Set findvalue = Sheet11.Range("A" & cPayroll)
    'add the database values to the userform
    cNum = 19
    For x = 1 To cNum
        Me.Controls("Reg" & x).Value = findvalue
 
        Set findvalue = findvalue.Offset(0, 1)
    Next
    'disable adding
    Me.cmdAdd.Enabled = False
    Me.cmdEdit.Enabled = True
    
    ' deal with textbox formatting issue
    Reg6.Value = Format(Reg6.Value, "h:mm AM/PM")
    
    'error block
    On Error GoTo 0
    Exit Sub
errHandler::
    MsgBox "An Error has Occurred  " & vbCrLf & "The error number is:  " _
           & Err.Number & vbCrLf & Err.Description & vbCrLf & _
           "Please notify the administrator"
           
           
End Sub