### Godot version

4.0.3-stable

### System information

Windows 10

### Issue description

In some projects ViewportTexture remains pink and doesn't render viewport content after upgrading from 4.0.2-stable to 4.0.3-stable. If a pair of files viewport.h/viewport.cpp are downgraded back to what they were in 4.0.2-stable, problem goes away.

This is how it looks in 4.0.3-stable:
![4 0 3_stable_viewport_4 0 3](https://github.com/godotengine/godot/assets/1449921/44c191a9-4b67-4b02-90b6-4ab615f62a73)

And this is how it looks if viewport.h/viewport.cpp are downgraded back to what they were in 4.0.2-stable.
![4 0 3_stable_viewport_4 0 2](https://github.com/godotengine/godot/assets/1449921/f5abc605-f129-4222-9c0e-e9a07621dd9d)



### Steps to reproduce

Unfortunately, I cannot come up wit a simple demo project reproducing the problem. It exists in some projects and doesn't exist in others.


### Minimal reproduction project

Cannot produce a simple project reproducing the problem. In simple projects it works fine.
break;
						}
					}
					if (ci->is_set_as_top_level()) {
						break;
					}
					ci = ci->get_parent_item();
				}
			}
			bool stopped = gui.mouse_focus && gui.mouse_focus->can_process() && _gui_call_input(gui.mouse_focus, mb);
			if (stopped) {
				set_input_as_handled();
			}
			if (gui.dragging && mb->get_button_index() == MouseButton::LEFT) {
				
				_perform_drop(gui.mouse_focus, pos);
			}
			_gui_cancel_tooltip();
		} else {
			if (gui.dragging && mb->get_button_index() == MouseButton::LEFT) {
				_perform_drop(gui.drag_mouse_over, gui.drag_mouse_over_pos);
			}
			gui.mouse_focus_mask.clear_flag(mouse_button_to_mask(mb->get_button_index())); 
			if (!gui.mouse_focus) {
				
				return;
			}
			mb = mb->xformed_by(Transform2D()); 
			Point2 pos = gui.mouse_focus->get_global_transform_with_canvas().affine_inverse().xform(mpos);
			mb->set_position(pos);