Front Suspension Popping Noise

[mmj]

New guy and have a question.
Have a 2008 Cayman S with 56K miles. Recently developed an intermittent popping noise from the front left strut area. Seem to hear it most on low speed bumps and when getting out of the car when the strut extends. Have already replace the upper strut bearings several thousand miles ago for making noise when turning. This noise is different. I've put the car on jack stands and removed the wheels and lower front cover looking for something obvious, but everything looks tight and not seeing any leaking or torn boots. My first thought was sway bar links or sway bar bushings, but the links turn smoothly and don't seem to have any play.
What do the experts here think?