A window should not get activated or get input focus if it's behind the lock screen.

ui/views/widget/widget.cc

Index: ui/views/widget/widget.cc
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index 3effd1b4d9e86dde9fdbc75fd2e1441a6fcbd77c..220e4c6f1b0e81d6ebeae54b6c659b74eb4dc741 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -1317,7 +1317,7 @@ bool Widget::SetInitialFocus(ui::WindowShowState show_state) {
       show_state == ui::SHOW_STATE_MINIMIZED) {
     // If not focusing the window now, tell the focus manager which view to
     // focus when the window is restored.
-    if (v)
+    if (v && focus_manager_.get())
       focus_manager_->SetStoredFocusView(v);
     return true;
   }