IIRC, Favero ended up swapping the springs to a lighter force range due to some complaints that the release was too stiff, even when set fully loose. I think the black springs are the newer, lighter force ones vs the silver black ones.
Either way, I mention it since this single factor could relate to some of the different experiences.
ETA: (I changed the colors above to match the hit from this page.)
The Favero Assioma Replacement Pedal Body is a direct replacement for the ones on your Favero Assioma power meter pedals. These pedal bodies feature improved aesthetics and the upgraded black spring that Favero released in mid-2019.
The new spring has a wider release torque tension. Specifically, the spring’s release torque tension range is from 8Nm to 20Nm (vs. 11Nm to 20Nm in the old pedal bodies). This wider range allows for lower release tension which makes the pedals easier to clip in and out of.
Considering the fact that the change only seems to apply at the lower release forces, it might not be a difference here for people that are using middle to higher forces. But may apply for those at the lowest tension for each spring design.