Is the rear triangle or dropouts supposed to squeeze and narrow?

I found myself having to adjust my disc brake position to prevent run after reinstalling rear wheel. I was pretty sure I had set it up before taking it off, so thought it was odd as I thought with through axles the position of the wheel would always be the same.

Then I noticed one part of my axle rotates, bear the head. Can’t recall if that was the way before but can’t see how that would affect anything.

But as I tightened down the wheel, I could see the dropouts get closer together.

I thought that only happened with quick releases?