I've set up a character rig with symbols and layer parenting. When I click the "Flip Horizontal" option, my character model becomes deformed and the symbols aren't where they are supposed to be.
How can I fix this?
Either set up your character rig so that the flipped states are within the symbols (so that you get the mirrored version by referring to a frame and not by flipping) or explore more flexible and flip-able systems, such as Smart Magnet Rigs.
Make sure your registrationpoint is in the right spot you want to flip it.