Outlook 2016 showing "Untitled attachment..."

So the main reason that I bought Office 365 for business was to fix the "Untitled attachment" bug that was showing up on my Outlook 2013.

The support forums stated that the bug was only present in the "older versions of Outlook".

I've just found the same bug in Outlook 2016. The Untitled attachment contains the signature of the sender.

The account is an IMAP account linked to G-Suite, and on the G-Suite webmail interface there is no "Untitled attachment" and the sender's signature is showing fine.

This is obviously the same client-side bug that is present in the older versions of Outlook.

Please tell me how to fix this bug ASAP.