Filed as FB24528594 with a minimal single-file repro. One finding worth adding to this thread: the collapsed-bar breakage doesn't need the .title item at all. With .inlineLarge and only a custom ToolbarItem(placement: .largeTitle), every scroll collapse leaves the collapsed bar with no title, no bar material or edge treatment, and content drawing through the status bar; it recovers on re-expansion. A .largeSubtitle item alone doesn't trigger it, and adding one to the .largeTitle item breaks the same way with the subtitle content vanishing too. Reproduced 100% on the iOS 26.5 simulator (Xcode 26.6), light and dark. No workaround found; navigationItem.titleView doesn't hold because SwiftUI re-renders the compact title after toolbar churn.