that_duck: > How did you make the resource unique? By clicking the dropdown menu next to the field in the Inspector and hit “make unique”. I am not sure how to “remove the uniqueness”. I deleted the resource and created new ones (both for the `StaticTile` class and the nested `TextureAsset`) and saved it as a `.tres` file. The method in question is triggered when a new value is assigned to the `StaticTile` field. When I assigned the new `.tres` file I got the same error again. Thanks for your support btw, it is highly appreciated!

that_duck: > You may be shadowing another variable. What happens when you rename texture_asset in your for loop? Good idea! But that call is within another class that doesn’t have another `texture_asset` property. I tried renaming the local variable to `texas` and I am still getting the error. `tile_textures` is a parameter of the function at hand and passed down through several method calls: func _get_tileset_source_from_tile_types(tile_textures: Array[TextureAsset]) -> TileSetAtlasSource: The value of this array that we are working with here is probably the one created by this method: func _get_textures_from_tiles() -> Array[TextureAsset]: var texture_assets: Array[TextureAsset] = [] for tile in tile_types: if tile != null: texture_assets.append(tile.texture_asset) return texture_assets

Nothing in your code jumps out at me as wrong. That being said, I am looking at Array[TextureAsset] and this in your initial post … sds29: > I even made the object unique … and thinking that there may be something in conflict there. How did you make the resource unique? What happens if you remove that uniqueness?