PowerPoint losing Shape Tags in "Art::GVML ClipFormat" when using Clipboard.GetData() / Clipboard.SetData()

I have a picture in PowerPoint with several shape tags on it. If I copy this picture to the clipboard, save the available data formats with Clipboard.GetData() and later try to restore it with Clipboard.SetData() I seem to lose the tags associated with the picture when pasting into PowerPoint (I can paste special as SVG or Microsoft Office Graphics Object).
I compared 1) clipboard data when copying the picture from PowerPoint and 2) clipboard data after my save and restore of the clipboard data and all the dataformats are the same and the sizes are also the same.
So why am I losing the tags and what can I do about it?
Thanks
Hi @Emi Zhang-MSFT unfortunately I still haven't received any reply. Is there anywhere else I can ask my question or send it to MS PowerPoint Team directly?