Markdown used to render into a preview on iOS when selecting a .md file. Now it just shows a blank screen. Requesting this gets fixed, I used this feature quite a bit and it's been broken for some time now.
When searching for this problem, an exact match shows up on google, however it appears the post was removed from the community boards. I can view the cache of the site, someone reported this problem back in May.
Let me know if you need any more information, I'd be happy to help any way I can to get this bug fixed.