So yeah, funny thing… for technical reasons, a site's tag-to-highlight-language mapping cannot be empty, therefore we had code that just inserted the "default" highlighting for the default tag if there was no other mapping. The question in question has that tag, and that's why that happened.
I've removed that default mapping, it's not necessary ...
There's a bug in the updated version. I've sent you a pull request with the fix (you'll have to regenerate the other files) and updated our version, including this fix. The new version is now live.
Thanks for the update!