Every time some philosopher comes up with a variation of "this machine cannot be said to understand what it is doing as opposed to simple mimicry" my response is always "I think the exact same about you" and so far I haven't seen any convincing argument to establish that there is a way to make one of these statements true while the other is false.
In other words, "understanding" is an illusion. It is indistinguishable from "simple mimicry".
I'm all for setting the goalposts in a way that chatbots are capable of "intelligence" but this is maybe moving them too far down. If humans aren't capable of understanding then nothing in our world is. Instead of arbitrarily changing the meaning of the word to no longer have any real meaning, let's adjust our interpretation of it into something that's actually meaningful. Personally, my mental concept of the word "understanding" already is satisfied by actions I and other humans actually are capable of demonstrating.
Being able to consistently mimic actions you've witnessed in a useful way is enough to demonstrate some understanding. Novel creation is not necessary.
In other words, "understanding" is an illusion. It is indistinguishable from "simple mimicry".