IK rig squishes joint when adding pole target

Question

I'm not quite sure what's happening as I'm new to modelling and rigging, but for some reason, when I add a pole target to the IK, a weird thing happens to the elbow joint. I've identified that what's happening is that for some reason, when I add the pole target, the IK rig decides to push the arm in the opposite direction than it did before, causing a weird squishing effect.

I know that the bones in the arms aren't perfectly straight, and I'm sure the pole angles are as correct as they can be, but this issue persists. When I don't use a pole target, however, it works as normal. I do need the pole target to control the angle of the elbow, though, so I'm not quite sure what to do.

The top image shows the rig with the IK pole target selected, and the bottom image shows the rig without the IK pole target selected. Added the axis to possibly provide insight.

Answer 1

I figured it out. Apparently, although the roll of the bones were correct in edit mode, and without the pole target, when I added the pole target, the IKed (the bone that had the IK modifier) bone rolled enough that it inverted the way the bones were meant to go. Changing the pole angle doesn't help with this, instead, rotating the IKed bone (not any other bones that are effected by the IK) in a way that the bone was going in the correct inversion, where then I could use the pole angle to put it in the actual intended direction.

See these two images:

This first image has the IKed bone with 0 rotation from default.

The second image has the IKed bone with a rotation that correctly inverts the bones.