I apologise if this issue has already been reported.
So I have just received the large lander, and I go on the second mission in Kaiser crater. I have a good landing, I go through the tasks. Then I get to the APXS task, or the scoop task, or any that involves me touching the ground with the arm. As soon as I even tap the ground, the lander goes back up into the air, and lands again. The sound effect of the thrusters are constantly playing, even when landed. I had this bother with the second mission in Victoria crater (small lander) as well.