I've actually had two in-person interviews that did this. They were old bugs in open source libraries that had already been fixed, but obscure enough that I was

I've actually had two in-person interviews that did this. They were old bugs in open source libraries that had already been fixed, but obscure enough that I was unlikely to know them. You solve the bug sitting with the reviewer. I don't think I had to actually fix them (though we talked about potential fixes), just identify the issue. The only one I remember was in the Python requests library. I felt like it was a pretty good real-world test.