spacebar shortcut for "zoom to fit" is broken

On mac os tahoe 26.3.2, the spacebar “zoom to fit” stops working correctly after zooming into a couple of photos. I expect the image to fit to whatever working window the app has available. But when it stops working and I hit spacebar, the zoomed image seems to be zoomed to fit to a completely different window size, it’s maddening. The only way to fix it is to reload one of the ui elements (as in, hide the editing pane and reshow it). It works properly while I edit another image or two, then it invariable breaks.