Is it normal that file and folder selectors are treated as normal windows in window rules?

I’ve been trying to setup an “initially maximized“ window rule for Gwenview, but whenever I copy images from within Gwenview, the folder (or file) selector is also initially maximized (which I do not want), despite the fact that I configured the window rule to only apply to normal windows, and not dialog windows.

I checked other apps (KTorrent and Kile), and the behavior is the same.

Is it intended behavior? If so, how do I achieve what I want? If not, which component should I report the bug for?

ETA: I checked Firefox and it works the way I want it to.

I’m using Plasma Wayland on an up-to-date Arch system if that helps.