The maximum age of a bug in a bug tracker is not really a meaningful metric. All software has bugs, and all large, widely used software has some problems or limitations that no-one is working on. You can close those issues to tidy things up, but that's also a good way to annoy people.

So the only conclusion you can really draw from "one bug was 11 years old" is that they had been using that issue tracker for at least 11 years.