Well, they're concerned with Gettier problems etc too.
But yeah the problem what you mean by "knowing." For example, I am perfectly happy to say that a LLM "knows" words just like I "know" words, or that it "knows about" very popular topics in a loose sense.
But that's a very different sense of "knows" from the kind of specific propositional knowledge we're usually interested in when using a LLM as a search engine, fact checker or source of information!
FWIW, although 'justified true belief' is classic in the sense of being an old definition of knowledge, I don't think any significant number of modern philosophers would use it.