Hey y'all- it seems that there is a clicking sound emanating from my headset that seems to be getting progressively worse- better some days than others but ever present. It started a few hundred miles ago (now have about 2500 total miles on it), at which time I serviced the bearings- which all looked good, greasy/no rust/no grit, and rotated without any detenting or grinding. Servicing made no difference. Tightening 15mmQR no difference.
I can reproduce the sound by locking the front brake and pushing the bike forward or pushing it against a wall/truck bed, and then re-do it pushing the wheel forward loading in the opposite direction- either action loading the headset in either direction. Once it clicks, I can't get it to do it again until the opposite pressure is applied. It also does it when clamping down in my 1UP rack which loads the front end against the rear wheel. Of course these motions are normal on the trail with braking and squishing and braking and squishing- all day long!

Forks are smooth and quiet through their stroke. It has the stock FSA ACB headset. Can the race(s) get loose either in the head tube or around the fork stem to cause a click?

TIA for any guidance