Paste from Windows clipboard does not trigger content changed

I am pasting from a source external to LO, which content does land appropriately in the target cell. However, I am not getting any raised onContentChanged events. Strangely, I can re-copy from the LO cell and paste again, then the EH happens. Why is that? Is it onChanged or onContentChanged, regardless, I do not see that event raised. onChanged I think it is.