### Godot version

v4.0.beta14.official [28a24639c]

### System information

Windows 10, OpenGL

### Issue description

Vulkan and Mobile:
![Godot_v4 0-beta14_win64_kEcRNiMfNJ](https://user-images.githubusercontent.com/7782218/213967627-8e8755d9-2fe2-43b3-b197-f9f2840b7580.gif)

OpenGL:
![Godot_v4 0-beta14_win64_MQ233TZuPq](https://user-images.githubusercontent.com/7782218/213967651-ae463a6f-c867-4312-bdf1-525e1d7def01.gif)

At first I thought it was related to `set_buffer()`, but it turned out that `set_instance_*` also work incorrectly.
Probably the custom information is also set incorrectly, but I haven't checked it yet.

### Steps to reproduce

* Open MRP
* In the editor, select `MeshInstance3D` node and change the `Count` property
* -- or --
* Start the project and move the slider

You can also switch the renderer to Vulkan and compare.

### Minimal reproduction project

[set_buffer().zip](https://github.com/godotengine/godot/files/10476834/set_buffer.zip)

Mesh::Surface::Attrib attribs[RS::ARRAY_MAX];
	int attributes_stride = 0;
	int vertex_stride = 0;
	int skin_stride = 0;
	for (int i = 0; i < RS::ARRAY_INDEX; i++) {
		if (!(s->format & (1 << i))) {
			attribs[i].enabled = false;
			attribs[i].integer = false;
			continue;
		}
		attribs[i].enabled = true;
		attribs[i].integer = false;
		switch (i) {
			case RS::ARRAY_VERTEX: {
				attribs[i].offset = vertex_stride;
				if (s->format & RS::ARRAY_FLAG_USE_2D_VERTICES) {
					attribs[i].size = 2;
				} else {
					attribs[i].size = 3;