when i insert a keyframe with a single bone selected to a ik chain does not animate properly when i insert at least 2 keyframes with a single bone selected with auto ik activated to control a 5 ik chain does not animate properly, i press g to move this one single bone (head bone there) and its shows me how it deforms but when i insert the keyframe with LocRotScale, and this single bone selected, and then i play the timeline this bone just moves itself but not how it was showing with auto ik... some video here for better understanding... 
https://youtu.be/ty0dATaQOw8
well the solution was to select all bones of the armature when going to insert instead a single one, and then ik chain works again, but still this is not normal tho...