I did find the route cause in my code:
Error if code fragment looks like:
Public Sub Page_BarButtonClick (Tag As String)
Select Tag
#If B4A
Case "Back"
...
#End If
End Select
End Sub
No error if code fragment looks like:
Public Sub Page_BarButtonClick (Tag As String)
#If B4A
Select Tag
Case "Back"
...
End Select
#End If
End Sub
Ideally, if B4i compiler will raise error in this situation before sending to Objective-c compiler