Yes i have the same problem. When sitting in camp, sometimes i sit on the ground, sometimes halfway in the ground, soletimes under the ground so invisible. I had 2 clipping problems with movie sequences. The one were Astarion bites you, and the first dream. My character is placed half in the other characters. Also Astarion is biting in air....

Which race are you playing? I had this with dwarf but not with half elf. Think it has to do with the length of your character?