### 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->use_xr == p_use_xr) {
		return;
	}
	viewport->use_xr = p_use_xr;
	
	
	if (!p_use_xr) {
		viewport->view_count = 1;
		_configure_3d_render_buffers(viewport);
	}
}
void RendererViewport::viewport_set_scaling_3d_mode(RID p_viewport, RS::ViewportScaling3DMode p_mode) {
	Viewport *viewport = viewport_owner.get_or_null(p_viewport);
	ERR_FAIL_COND(!viewport);
	viewport->scaling_3d_mode = p_mode;
	_configure_3d_render_buffers(viewport);
}
void RendererViewport::viewport_set_fsr_sharpness(RID p_viewport, float p_sharpness) {
	Viewport *viewport = viewport_owner.get_or_null(p_viewport);
	ERR_FAIL_COND(!viewport);
	viewport->fsr_sharpness = p_sharpness;
	if (viewport->render_buffers.is_valid()) {
		viewport->render_buffers->set_fsr_sharpness(p_sharpness);
	}
}
void RendererViewport::viewport_set_texture_mipmap_bias(RID p_viewport, float p_mipmap_bias) {