The first version of Liftoff had no problems with self-righting because as you said PJ, the design of lifting arm acted also as a self righter...but there were also disadvantages to that design.
The hinge point was at the very edge of the machine and the ram was vertical, the recoil caused the robot to flip upside down when it missed the target. And to be able to self right properly I had to decrease the usable pressure to around 7bar or less as otherwise it would somersault and end up upside down again!

So I redesigned the system placing the hinge mid-way on the machine, and with the ram in horizontal position hoping to eliminate the tendency of the machine to flip upside down when it misses the target.

I could try to redesign the the flipper hinge so that it would travel further up and act as a self righter - but I fear it would be in a too much of a mechanical disadvantage