Spine.set_position unexpectedly clears axis

I’m setting up an axes in which I configure the axis objects with my desired tick locators and formatters and later configure the spines, setting their bounds, visibility, and positions. I was surprised that setting the spine position wiped my axis formatting by calling axis.cla(). Is it necessary that the spine must clear the registered axis when its position is changed? (The same clearing occurs in Spine.register_axis(), but in my case that occurs at axes creation and doesn’t cause me any trouble.)