Index page content disappears

My Computer Science work .io page is organised into folders (with a little script I wrote to generate the page indexes). As of a fairly recent push, my index pages are no longer working (my other pages are working and use the only questionable character in the index pages - ←)

Example of working page 

Content of an index page (proves that the page exists) 

Direct index link 

Implied index link (same folder) 

Could somebody tell me what’s going wrong with my page (or, if it’s fixed, let me know that it’s working again)

Should most likely be a separate thread, but in addition, my file does not seem to convert to the page at all; / shows the raw content of the file but /README.html redirects me to the 404 page

Turns out pages doesn’t like UTF-16. Converted to UTF-8 and index pages work again