I believe I am an expert Illustrator user, but I've never seen this weird behavior before.
The Align setting is set to "Align to Selection". However when I click "Horizontal Align" or "Vertical Align", the objects move away from each other. Each subsequent click on the Align Panel moves them further away from each other.
I tried resetting Bounding Boxes in the Transform panel, which proved fruitless.
Am I doing something wrong, or is this the latest Illustrator glitch?