yes I’ve had/got this on mine, I only really noticed it on small bumps to be honest, ive had them serviced and it seems better, but still there to some extent, its in the initial bit of travel/sag on the forks as it returns to full length, once it gets deep in the travel I haven’t heard it at all (maybe just cant hear it as descending), its more so when you are climbing/flat on anything with bumps in it I notice it more
it does sound exactly like you say though a headset knock or similar, I can notice it more on mine just pushing down slowly at home in silence, but when out its not as audible with out side elements….
im not sure what it is either as I said mines is quieter after a service but its still defo there