I can reproduce this on iPadOS 26.6.2 and iOS 26.5, with a Screen Time passcode set and Content & Privacy Restrictions enabled. One detail that may help narrow it down: the same switch enforces the Screen Time passcode correctly when reached via Settings > Screen Time > Apps with Screen Time Access. Only the per-app page at Settings > Apps > falls back to device owner authentication, and from there the device unlock passcode is accepted. Filed as FB24852929