Bones move to a position without keyframes?

Hi peeps

I made a character and rigged it with bones. The bone structure looks like this in bone edit mode:

And this is how it looks in pose mode (set in “rest position”):

As you can see I’ve set some IK’s and parents and stuff and it all works as it is supposed. I made a small test animation to check it out, and later on removed EVERY single one keyframe and resetted the bone poses with ALT+G and ALT+R.

Yet, whenever I enter “pose mode”, arm bones move around a bit:

Why on earth is this happening? I have resetted the bone location & rotation already and I have no keyframes whatsoever. What causes this?

Possible the bone roll angle. Or they are pointing at targets.