bevy_pbr 0.16.0-rc.4 - Panics when despawning a Mesh in 'Last'

[dekirisu]

Bevy version

bevy 0.16.0-rc.3
with bevy_pbr 0.16.0-rc.4

What you did

Despawning a Mesh in the Last schedule at a later time as spawning.

Minimal code:

use bevy::prelude::*;

fn main(){
    let mut app = App::new();
    app .add_plugins(DefaultPlugins)
        .add_systems(Startup,startup)
        .add_systems(Last,despawn)
        .run();
}

fn startup(
    mut cmd: Commands,
    mut ass: ResMut<Assets<Mesh>>,
    mut ase: ResMut<Assets<StandardMaterial>>
){
    cmd.spawn((
        Transform::from_xyz(0.,0.,5.),
        Camera3d::default(),
    ));
    cmd.spawn((
        Mesh3d(ass.add(Cuboid::new(1.,1.,1.))),
        MeshMaterial3d(ase.add(Color::srgb(1.,0.,0.)))
    ));
    cmd.spawn(DirectionalLight{
        shadows_enabled: true,
        ..default()
    });
}

// despawn after 2 seconds
fn despawn(
    mut cmd: Commands,
    query: Query<Entity,With<Mesh3d>>,
    time: Res<Time>,
    mut delay: Local<f32>
){
    *delay += time.delta_secs();
    if *delay < 2. {return}
    for e in &query {
        cmd.entity(e).despawn();
    }
}

What went wrong

Running it (on linux 6.13.8-arch1-1 btw) always panics here:

thread 'Compute Task Pool (23)' panicked at ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_pbr-0.16.0-rc.4/src/material.rs:1014:79:
called `Option::unwrap()` on a `None` value
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Encountered a panic in system `bevy_pbr::material::specialize_material_meshes<bevy_pbr::pbr_material::StandardMaterial>`!

If a DirectionalLight with enabled shadows is present, it also panics here:

thread 'Compute Task Pool (15)' panicked at ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_pbr-0.16.0-rc.4/src/render/light.rs:1820:84:
called `Option::unwrap()` on a `None` value
Encountered a panic in system `bevy_pbr::render::light::specialize_shadows<bevy_pbr::pbr_material::StandardMaterial>`!

Additional information

• It's easily avoidable by despawning in any schedule before Last.
• but afaik: this worked in bevy_pbr 0.16.0-rc.3