I know I am late for the party but this may help any future visitor so I will go ahead and post a solution.

The .Find is happening on wsWFD.Columns("E") so .FindNext should happen on that range.

Code:
Set rngfound = wsWFD.Columns("E").FindNext(rngfound)
BTW, deleting in a loop can be extremely slow. You may want to identify the rows that you want to delete and store them using UNION. Finally at the end of the code delete it all together.

Something like this (UNTESTED)

Code:
    Dim DelRange As Range
    Dim rng As Range
    Dim bCell As Range
    
    Set rng = wsWFD.Columns("E")
    
    With Sheet1
        For lngRow = 2 To lngLastRowT
            Set rngfound = rng.Find(.Cells(lngRow, "E"), LookIn:=xlValues, LookAt:=xlWhole)
            
            If Not rngfound Is Nothing Then
                Set bCell = rngfound
                                    
                Set DelRange = wsWFD.Rows(rngfound.Row)
                   
                Do
                    Set rngfound = rng.FindNext(rngfound)
                    
                    If Not rngfound Is Nothing Then
                        If rngfound.Address = bCell.Address Then Exit Do
                        
                        If DelRange Is Nothing Then
                            Set DelRange = wsWFD.Rows(rngfound.Row)
                        Else
                            Set DelRange = Union(DelRange, wsWFD.Rows(rngfound.Row))
                        End If
                    Else
                        Exit Do
                    End If
                Loop
            End If
            
            If Not DelRange Is Nothing Then
                DelRange.Delete
                '~~> Set the range to nothing after deleting
                Set DelRange = Nothing
            End If
            
            '~~> This is important to avoid false positives
            Set rngfound = Nothing
        Next
    End With
PS: Long time! How have you been?