We are happy to notify you that these issues appear to be resolved by Microsoft.
We are aware of issues relating to previewing emails and converting Office documents to PDF.
Our engineers have advised that the issue originates from the Microsoft APIs used for these processes, and a ticket has been logged with Microsoft.
As a temporary workaround:
Please note that while the preview will be quicker to display, formatting of the document content may not be accurate, especially for more complex documents.
Apologies for any inconvenience caused, we will provide further updates as soon as they become available.