I initially discovered the issue when I was attempting to pre-format a large block of text that I needed to be indented four spaces inside the code block; that is, effectively indented eight spaces. There was no easy way to do that in-editor (other than copy/pasting eight spaces repeatedly) so I tried to use code fences instead.
the only way to do this is eight spaces
or via code fence and four spaces
Four spaces is advantageous over eight because I can use the in-editor Preformatted text button to indent large blocks of text by four spaces, but there’s no way to do that with eight. This is obviously not a common use-case, so it’s not a particularly high priority bug.