I have the exact same problem too. I can never get a placement without turning off Parallax. Ground experiments placed down without Parallax, then visited with Parallax installed again are either half sunken in the ground, or have a visit of the kraken and jump up in the sky.
Lander legs are bouncing around too, but I can solve that for the most part with playing with damping and spring strength.
Which is a shame, because everything looks amazing. Would really like to keep playing with the mod.