Mine drops a couple inches while traveling on the left side. I think the only thing that stops it from going further is the safety pin. I often have to lower it all the way down and then all the way back up until it times out...this always straighten it out.
The remedy is to re-sync the motors. Drop the bunk down completely. Hold the switch down for two-three seconds after it reaches the bottom, (and hopefully both motors take it all the way down). Then, raise the bunk all the way to the top, without stopping or pausing, until it's at the top, and hold the switch for two-three seconds.
Also, remember to hold the switch for 2-3 seconds after each time you raise or lower the bed.
That sync method, should be used also on Thor's 2 motor slides too. If they are allowed to get too far out of sync, you can find yourself with a jammed slide. Easy to avoid, though, using the 3 to 5 second continued button depress after the slide is open or closed.