I'm not sure if this has been discussed before but I seem to be having trouble when going to land on the Moon. Principia was the only mod I added before I started having the problem. I started using Principia with RSS/RO/RP-0 and it's been working great but last night I went to land a probe on the surface of the Moon and as I got near the surface the whole thing was vibrating up and down. My first couple attempts the probe clipped through the ground and got destroyed.I made sure I had the latest version and tried again. The surface was still vibrating wildly but my craft didn't clip through the ground. It kept bouncing off the surface until the whole thing was destroyed. I also noticed at about 60km up when timewarping there is a noticeable drop in altitude depending on the speed of the timewarp. I think I saw a change of ~1.5km. I'm not sure if it's something I'm doing wrong to cause it.