Tested versions

Reproductible in 4.6

System information

Linux - Godot 4.6

Issue description

I was looking for identifying properly several properties (destructible/ricochet/effect...) of my grid map items colliding with weapons bullets and I noticed that MeshInstance3d metadata are not accessible when exported as MeshLibrary.

Steps to reproduce

Create metadata on meshes from a MeshLibrary. Export as library to use with a gridmap. Get programmatically meshes from the grid map and try to access metadata.

Minimal reproduction project (MRP)

var gridmap: GridMap = body as GridMap
var mesh_lib: MeshLibrary = gridmap.mesh_library
var item_id = 1 #mesh id with metadata
var mesh: Mesh = mesh_lib.get_item_mesh(item_id)
var is_destructible: bool = mesh.get_meta("destructible", false) as bool #return default value

var meta_list = mesh.get_meta_list()
print("Mesh metadata keys:", meta_list) #return empty list []