Not sure why this is happening. What is the relationship here?

Banned name: .wmf,docProps/thumbnail.wmf
Content type: Banned
Internal reference code for the message is 26135-14-5/Qep0YTJfyTmt

From the banned email
Content-Type: application/vnd.openxmlformats-officedocument.presentationml.presentation;
name="Physicians Group IC.pptx"
Content-Transfer-Encoding: base64
Content-Disposition: inline;
filename="Physicians Group IC.pptx"