web PR diff viewer fails to show contents of files with spaces in the name?

I'm not 100% sure it's the spaces, but I'm not sure what else it could be.

for example, I click on a file named "API - Javascript.md" - the end of the URL now looks like this: pull-requests/106/diff#docs/API - Javascript.md however in the right panel, the contents for a DIFFERENT file - app/config/api.yml - is shown. I don't know if it's matching the string before the space "API" -> "api"? or if it's just that app/config/api.yml happens to be the first file listed in this diff.

I've tried reloading the page, clicking on this in various ways, etc, but the diff for the "API - Javascript.md" file refuses to load.

I remember I've had this issue before, but I forget what the name of the file was. I figured it was just a fluke, or something odd about that PR. but seeing it happen again, I have to wonder if there's an actual bug with the diff viewer.