We have seen this in Alfresco Content Services 7.2 also. It impacts all Microsoft documents (Word, Excel, PowerPoint). For the sake of others who may read this, here is more detail about the issue, resolution, and a quick workaround:
While logged in as a user with any role-based permissions except Consumer, you are unable to edit documents using the “Edit in Microsoft Office” function. When you click the “Edit in Microsoft Office” command to edit a document, the desktop app appears to launch. However, the document is blank and opens to a blank, grey screen.
This can occur if HTTPS for Alfresco Office Services (AOS) is added with an IP address instead of a fully qualified name.
Add HTTPS for AOS with the fully qualified name, not just the IP address.
You can quickly work around this by editing documents offline instead of in MS Office. Alfresco's online documentation includes instructions for editing files offline: