Shapes within shapes pasting offset. Geometry out of whack?

Hi folks. Just another wee glitch I hope someone knows the resolution for. I also have no idea how to title these threads for SEO.

So I have an icon that I want to place within a shape to create a media control button. I have the shape ready to go.

I download the icon from the built-in library and size it and have it ready to be inserted into my shape.

I select both objects and just align them so the icon is bang-on in the middle of the shape.

I then copy and delete the icon, select the shape, click the Edit States button, and deselect the default shape...

and simply paste the icon in...

... only to have it place mathematically offset by the width of the original shape.

The box shape container hasn't been shifted from its XY 0,0 axis as can be seen from the blue cross and neither has it been flipped or mirrored.

No idea why this is happening. Anyone got any ideas?