Sub-directory redirects to 404 page at root instead of index.html inside

My site has a 404 page that just redirects to the index.html at root (e.g. www.param.me/foo redirects to www.param.me since it doesn’t exist) That works as expected…

However, I have a sub-directory called /old with an index.html inside. When I navigate to www.param.me/old, instead of redirecting to www.param.me/old/index.html, it redirects to the root 404 page

Github repo

EDIT: I checked back 4 hours later and it seems to work now… I guess Github Pages just needed some time to recognize /old as a valid sub-directory

Yeah, I’ve noticed this also. 

For example:

https://rdil.rocks/hdgfuidhfiguhsuig

vs

https://rdil.rocks/gfsjdg/ffigisdjg

I checked back 4 hours later and it seems to work now… I guess Github Pages just needed some time to recognize /old as a valid sub-directory