The problem I have with saying nothing is that the act of saying "still working on X" can be a trigger for more conversation. Is X taking longer than expected by the rest of the team? Let's dig into that. Did somebody else's work unexpectedly intersect with X yesterday? Now they have a mental trigger to mention that. Etc.
But, in practice, I'd prefer somebody gave a little more context than a simple "working on X" (assuming X isn't trivial - if it was, you would have finished it already) - what part of X... Design? Coding? Testing? Any roadblocks? Do you expect to turn it over to QA today or tomorrow? Nobody is working a vacuum and all our work intersects at some point.
But, in practice, I'd prefer somebody gave a little more context than a simple "working on X" (assuming X isn't trivial - if it was, you would have finished it already) - what part of X... Design? Coding? Testing? Any roadblocks? Do you expect to turn it over to QA today or tomorrow? Nobody is working a vacuum and all our work intersects at some point.