So Symmetry Flips the roll. Thus negative becomes positive and positive becomes negative. That is way the Axis are flipped. On the pole target, the bones with the IK constraints(the first in the chain) will have it’s X axis point towards the pole target. In this rig the main control/Bend axis is z. Thus you need to change the Roll. If you wanted to use X as the main bend axis then you would set the roll to so that X runs across the the knee instead the Z axis. Then you would use the Pole Angle to position it back after it twist to point the X at the pole target. They are used for different things.
For the getting out of sync, I’m not sure what you are talking about. If the Pole Target isn’t aligned correctly in combination with the roll and/or Pole angle being off you can get some undesired effects, but without seeing what it’s doing it’s hard to say what the issue is.
