Ah ok, that’s the relevant setting then.
I’m working with images that are around 500px tall and I guess some are a bit over and some are a bit under. I set them all to 35% scale so they fit together side-by-side but also with the idea that if you want a closer look you can use the lightbox like a gallery.
In this example only the first image lightboxes and also creates this strange positioning:
I agree this seems like a weird edge case and my intuition (and intention) was for all of them to lightbox in this case