### Godot version

v4.0.beta17.official [c40020513]

### System information

Windows 11, OpenGL (Compatibility), RTX 2060 (31.0.15.2824)

### Issue description

I tried to make a blurred panel for a ui element with texturelod via shader:

```glsl
shader_type canvas_item;

uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_linear_mipmap_anisotropic;
uniform float blur_amount : hint_range(0.0, 5.0);

void fragment() {
	vec4 blurred = textureLod(SCREEN_TEXTURE, SCREEN_UV, blur_amount);
	COLOR = blurred;
}
```

but what I got instead is this:
![image](https://user-images.githubusercontent.com/72286622/217170426-49f6712d-47ef-4c53-b9f1-30d8ad868084.png)

vulkan renderer does not exhibit this issue:
![image](https://user-images.githubusercontent.com/72286622/217170565-a013c712-94f6-49d1-b9ec-091c28a7790b.png)


### Steps to reproduce

1. Add a TextureRect node
2. Add a Panel node to overlay the previously added node
3. Apply the blur shader to the panel node

### Minimal reproduction project

N/A
RBMap<uint32_t, RenderTarget::RTOverridden::FBOCacheEntry>::Element *cache;
	if ((cache = rt->overridden.fbo_cache.find(hash_key)) != nullptr) {
		rt->fbo = cache->get().fbo;
		rt->color = cache->get().color;
		rt->depth = cache->get().depth;
		rt->size = cache->get().size;
		rt->texture = p_color_texture;
		return;
	}
	_update_render_target(rt);
	RenderTarget::RTOverridden::FBOCacheEntry new_entry;
	new_entry.fbo = rt->fbo;
	new_entry.color = rt->color;
	new_entry.depth = rt->depth;
	new_entry.size = rt->size;
	
	if (p_color_texture.is_null()) {
		new_entry.allocated_textures.push_back(rt->color);
	}
	if (p_depth_texture.is_null()) {
		new_entry.allocated_textures.push_back(rt->depth);
	}
	rt->overridden.fbo_cache.insert(hash_key, new_entry);
}
RID TextureStorage::render_target_get_override_color(RID p_render_target) const {
	RenderTarget *rt = render_target_owner.get_or_null(p_render_target);
	ERR_FAIL_COND_V(!rt, RID());
	return rt->overridden.color;
}
RID TextureStorage::render_target_get_override_depth(RID p_render_target) const {