Private Function ParamArray_Variant(ParamArray Params())
    ParamArray_Variant = Params
End Function

Dim v
v = ParamArray_Variant

• IsMissing(v) = True
  
• IsArray(v) = True
  
• LBound(v) = 0
  
• UBound(v) = -1

Dim a()
a = ParamArray_Variant 'Здесь нас ждет сюрприз в виде ошибки 5 "Invalid procedure call or argument".

Dim b()
b = ParamArray_Variant(1) 'ОК

Dim a()
Dim v: v = ParamArray_Variant
If Not VBA.IsMissing(v) Then a = v

Public Function ParamArrayDelegated(ParamArray prms() As Variant) As Variant
    Dim arrPrms() As Variant, arrWrk() As Variant
    'When prms(0) is Array, supposed is delegated from another function
    On Error GoTo ErrorHandler
    arrPrms = prms
    If UBound(arrPrms) >= 0 Then
        Do While VarType(arrPrms(0)) >= vbArray And UBound(arrPrms) < 1
            arrWrk = arrPrms(0)
            arrPrms = arrWrk
            If UBound(arrPrms) < 0 Then
                Exit Do
            End If
        Loop
    End If
    ParamArrayDelegated = arrPrms
ExitHere:
    Exit Function
ErrorHandler:
    Debug.Assert Not (STOP_AT_ERROR And IS_DEV) '>> remove in release
    Err.Raise Err.Number, "ParamArrayDelegated of bas_Utilities", Err.Description & vbCrLf & "in ParamArrayDelegated of bas_Utilities at " & Erl
    Resume '>> remove in release
End Function