[Plugin: W3 Total Cache] CDN not working for Internet Explorer

This is pretty odd, but when I use FF or Chrome, my images are all delivered via CDN (cloudfront), but when I view my site with IE, the images don’t come from the CDN. They are rendered fine, but come from my server, not the CDN. It’s not a browser cache issue, as I’ve cleared it and used another person’s computer too.

Any idea what might be causing this?

Site is: https://www.doseofdigital.com

Thanks,
Jonathan

https://www.ads-software.com/extend/plugins/w3-total-cache/