### Godot version

v4.0.beta12.official [3c9bf4bc2]

### System information

Windows 10, AMD Radeon RX 480 4 GB RAM, 16 gb ram, Intel CPU 4 cores.

### Issue description


When switching to mobile render from forward + The alpha texture on the tree mesh starts to flicker.
Made a video: https://www.youtube.com/watch?v=WdGVi1hdRHo



### Steps to reproduce

Switching to mobile render from forward +

### Minimal reproduction project

Uploaded the project in google link: https://drive.google.com/file/d/1efEV914CWkyWoGzkv3RBMnw9t-4BVTeQ/view?usp=sharing
(only deleted the .godot - i guess its not needed.)
Viewport *viewport = viewport_owner.get_or_null(p_viewport);
	ERR_FAIL_COND(!viewport);
	if (viewport->screen_space_aa == p_mode) {
		return;
	}
	viewport->screen_space_aa = p_mode;
	_configure_3d_render_buffers(viewport);
}
void RendererViewport::viewport_set_use_taa(RID p_viewport, bool p_use_taa) {
	Viewport *viewport = viewport_owner.get_or_null(p_viewport);
	ERR_FAIL_COND(!viewport);
	if (viewport->use_taa == p_use_taa) {
		return;
	}
	viewport->use_taa = p_use_taa;
	_configure_3d_render_buffers(viewport);
}
void RendererViewport::viewport_set_use_debanding(RID p_viewport, bool p_use_debanding) {
	Viewport *viewport = viewport_owner.get_or_null(p_viewport);
	ERR_FAIL_COND(!viewport);
	if (viewport->use_debanding == p_use_debanding) {
		return;
	}
	viewport->use_debanding = p_use_debanding;
	if (viewport->render_buffers.is_valid()) {
		viewport->render_buffers->set_use_debanding(p_use_debanding);
	}
}
void RendererViewport::viewport_set_use_occlusion_culling(RID p_viewport, bool p_use_occlusion_culling) {