I think that claiming we "do not know" if that is real understanding or imitation is a bit like claiming (to use a favorite example) that we don't know if a rock senses gravity when it falls. Of course, maybe even minerals have something like a "sense" (like bio matter has), but even in such a case the computer would again be having sense due to material acting like dna, not due to the actual program.
Now, in scifi territory, maybe even pure routines or other events may lead to some kind of sense. But this isn't what is being researched and even if it would exist it would have to be triggered specifically (I mean rocks don't seem to develop a sense just by gravity effecting them). We don't have such tech. What AI currently seems to be examined as is just programs somehow being more than a collection of programs, forming a focal point ala an ego, which isn't realistic with what we know. Sure, a thermostat doesn't have to know of what heat is, or words for it, or things related to it or metaphors about it, but it was actually an actor/had sense it should at least form some account of it which is built out of a pool of materials it has to form senses about. An ant, from what one can tell, does have a sense of the ground it moves in, regardless of what that actual sense may be, or of what the sensation of pheromones is, etc.
Maybe the matter gets complicated also due to prehistoric animistic beliefs (and their not conscious nor direct) remains in contemporary humans: at some time in prehistory I am pretty sure rocks or other such objects were imagined to have life of this kind. Not because prehistoric people were dumb, but because it is a very easy to express mental connection/thought.