Gist embed doesn't work for file with space in name

1. Create a public Gist in Github with multiple files in it.
2. Make sure that the name you specify for one of the files has a space in it (the specific file name I had problems with was "tasker datadescr.txt"0.
3. Save the gist, then click on the file name with the space in it and copy the reuslting URL form your URL bar.
4. Compose a new post in WordPress and past that URL into it.

At this point WordPress says it can't embed the URL.

When I ran into this, I was able to embed the URL after replacing the space in the file name with a hyphen and saving the modified Gist.