Are you running anti-tracker extensions? I am seeing the same thing in Firefox with Privacy Badger running. Apparently these kind of pages need images and other resources from medium.com, which is being detected as a potential tracker.
Chalk it up to defective website design.
Thanks, that seems to be the problem indeed.
I run into the same problem in Chrome, using Privacy Badger. However, the Mercury Reader extension does a great job reformatting the page for readability.
If you blocked medium.com to be usable for third party sites, all medium blogs under custom domains lack some resources.