Copy paste keyframes (not mirroring) moves IK bones

I’ve made my first rig with IK controls, and am now trying my first walk cycle with it. The arms and legs are rigged using a target and a pole target. The IK targets are children of the Root.

Posing the character works fine, but when I select all the bones from layer 1 (the IK targets and some FK bones), copy their keyframes and paste them (not mirrored, but normally), the legs are pasted mirrored, and the hand IK bones are moved outwards. The elbow IK pole targets are moved leftwards, and also the knee IK pole targets move.
I have checked all the bone namings, and they are as they should be (ending with .l or .r when symmetrical)

Any clue what can be causing this?

Here’s the blend file, if you’d like to try out. I’m using blender 2.62 (official build)
supervisor.blend (1.07 MB)

I could not look into the file since I’m on a mobile device. It looks like you might have some sort of IKchain loop dependence. maybe the IKtargets are connected to the IKchain? Generally speaking these two things (loop dependency or connected IKtarget) lead to your kind of problems - but as I said: I can’t check the file now.