I have tried at least 4 times with 3 separate ships to use the landing guidance to land on the Mun and Minmus but the landing guidance keeps trying to perform course corrections by spinning the ship backwards and forwards until either the ship crashes into the ground, or it somehow stops and moves on to the final descent stage where it performs its final burn which isn't enough to stop the ship from crashing into the ground anyway. The ships are simple landing pods with one fuel tank and a simple thruster. They all have RCS and SAS and are capable of rotating quickly and precisely in each case but MechJeb isn't quite happy with their directions and tries to correct this each each second (Mechjeb tries to warp between these corrections too). The landing guidance used to work before i updated it to match KSP 1.2. I tried your most recent dev build but it still won't work. I have attached the log. I hope I have provided enough information.