A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
The answer provided by Microsoft was tone deaf. If you are encountering the issue, you are not the problem. Your GIF probably isn't the issue, either. My GIFs play and loop just fine when I'm editing the slides in PowerPoint O365, but when I present, the GIFs are static. Animation doesn't help because I'm not trying to insert slide transitions and there is no "preview/properties" window.
I downloaded my presentation and opened it in PowerPoint desktop. I go to present and my GIFs work fine. This is the only work around I have found after wasting too much time scouring forums for answers. Download your presentation right before you plan on presenting if you want your GIFs to play in presenter mode.
Microsoft needs to fix this bug.