### 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.
ERR_MAIN_THREAD_GUARD;
	ERR_FAIL_NULL(p_viewport);
	ERR_FAIL_NULL(p_control);
	if (gui.mouse_focus) {
		p_viewport->gui.mouse_focus = p_control;
		p_viewport->gui.mouse_focus_mask = gui.mouse_focus_mask;
		p_viewport->gui.key_focus = p_control;
		p_viewport->gui.forced_mouse_focus = true;
		gui.mouse_focus = nullptr;
		gui.forced_mouse_focus = false;
		gui.mouse_focus_mask.clear();
	}
}
void Viewport::set_sdf_oversize(SDFOversize p_sdf_oversize) {
	ERR_MAIN_THREAD_GUARD;
	ERR_FAIL_INDEX(p_sdf_oversize, SDF_OVERSIZE_MAX);
	sdf_oversize = p_sdf_oversize;
	RS::get_singleton()->viewport_set_sdf_oversize_and_scale(viewport, RS::ViewportSDFOversize(sdf_oversize), RS::ViewportSDFScale(sdf_scale));
}
Viewport::SDFOversize Viewport::get_sdf_oversize() const {
	ERR_READ_THREAD_GUARD_V(SDF_OVERSIZE_100_PERCENT);
	return sdf_oversize;
}
void Viewport::set_sdf_scale(SDFScale p_sdf_scale) {
	ERR_MAIN_THREAD_GUARD;
	ERR_FAIL_INDEX(p_sdf_scale, SDF_SCALE_MAX);
	sdf_scale = p_sdf_scale;
	RS::get_singleton()->viewport_set_sdf_oversize_and_scale(viewport, RS::ViewportSDFOversize(sdf_oversize), RS::ViewportSDFScale(sdf_scale));
}
Viewport::SDFScale Viewport::get_sdf_scale() const {