Agree, autolayout rarely works as intended when you have many nested things like images and text, or in your case those icons.

Are the icons SVG? Figma is bad with SVG and has trouble reconciling the SVG artboard with its own. This is why when you make a frame longer with SVG images in it, it will randomly move the images down.

Curious if you make the arrows the same height as the rectangles if it works?