addNewKey not working

Hey there.

I created a "Key All" button in a UI that iterates through a bunch of controllers to set keys on position & rotation. addNewKey seems to be what I should use, but it just isn't working.

My rotation is a rotation_list, with three euler_xyz underneath it.
I want to key the third euler_xyz track on the current frame.

So, here's what I tried:

indirect method -
addNewKey $objectName.rotation.controller[3] currentTime

explicit method -
addNewKey $objectName.rotation.controller.ThirdRot.controller currentTime

Neither works. What happens is that once I addNewKey and then rotate the control, the values of the existing keys become the values of the control's current position.

I've looked into "on animate" but that doesn't seem to be what I want.

Any hints on what could be causing this behavior?