After cleaning the drivetrain on the El Mariachi Ti I was poking around with the bike, and when spinning the front wheel on the workstand I could hear something tumbling around inside of the front tire. It didn’t throw the wheel off balance, but as it was likely a Stan’s booger I figured I should remove it. After deflating and popping the tire off the bead, the ~4cm coagulated clump of latex was easily removed from the tire.
Once the tire was popped back on the rim I was able to reseat it using a hand pump, which made it very easy to get the wheel back together. With another ounce of Stan’s Sealant added into the front wheel to replenish what was lost, all is back to normal, and now there’s no rattly-tumbly sound when the wheel spins.