I think Henrik is right insofar as Unicode decimal 127-159 are undefined and as such should not be expected to map to visible glyphs (160 is a non-breaking space). But what MMA seems to be offering here is some ad hoc support for ISO 8859-15 characters. On Windows, as Konstantin noticed, this should result in no visible glyphs at all. On my Mac, however (MMA v12), it produces this:

So, I guess, to "fix" it, MMA would need to fully support 8859-15 for this range, and on Windows, ISO Windows 1252. But in today's Unicode world, both encodings are obsolete and the glyphs in this range have new encodings. Compare, for example (OSX only), the old and new encodings and glyphs for the Euro symbol :

So, probably, yes, it's still a 'bug' but one which is already fixed.