Its even worse when you force Firefox to use wayland its icon doesn’t even show.
Edit: Oh since everyone now is confused; I only have the flatpak version of Firefox installed yet it doesn’t use the pinned icon and doesn’t even use the firefox icon under wayland at all.
Yeah I’m a heavy flatpak user on both Gnome and KDE and this only happens on KDE for me. Maybe it’ll get sorted in Plasma 6.