Got some of the above forks and they instantly sink into about 15mm of the travel with minimal weight. They also seem to rattle and clunk going up a kerb for example.
They feel otherwise smooth and stiff after the initial dead travel.
Sagging on the bikes weight is normal, 15mm seems a bit extreme. I would say my Fox 36 will sag 3-5mm under its own weight. You should count this as part of your sag measurement.
The clunk doesn’t sound right, I don’t have experience with that fork, but clunking noises in suspension is usually not a great sign of things working correctly. Double check the headset is tight, that is usually the biggest culprit and can feel like it’s bushing play in the fork or coming from the fork.