0.12 bug: despawn + spawn during state change, without spawning texture, panics

[MeoMix]

Minimal Repro Repo: https://github.com/MeoMix/bevy_bug_example

Relevant Code:

use bevy::prelude::*;
use bevy_ecs_tilemap::{TilemapPlugin, TilemapBundle};

fn main() {
    App::new()
        .add_plugins((DefaultPlugins, TilemapPlugin))
        .add_state::<ExampleState>()
        .add_systems(Startup, (spawn_camera, spawn_tilemap_example))
        .add_systems(OnExit(ExampleState::State1), despawn_tilemap_example)
        .add_systems(OnEnter(ExampleState::State2), spawn_sprite_example)
        .add_systems(Update, change_example_state)
        .run();
}

#[derive(States, Default, Hash, Clone, Copy, Eq, PartialEq, Debug)]
pub enum ExampleState {
    #[default]
    State1,
    State2,
}

#[derive(Component)]
pub struct ExampleTilemap;

pub fn spawn_camera(mut commands: Commands) {
    commands.spawn(Camera2dBundle::default());
}

pub fn spawn_tilemap_example(mut commands: Commands) {
    info!("spawn_tilemap_example");
    commands.spawn((
        ExampleTilemap,
        TilemapBundle {
            ..default()
        },
    ));
}

pub fn despawn_tilemap_example(query: Query<Entity, With<ExampleTilemap>>, mut commands: Commands) {
    info!("despawn_tilemap_example");
    commands.entity(query.single()).despawn();
}

// TODO: Determine why this panics after despawning `TilemapBundle` components
pub fn spawn_sprite_example(mut commands: Commands) {
    info!("spawn_sprite_example");
    commands.spawn(SpriteBundle {
        ..default()
    });
}

pub fn change_example_state(state: Res<State<ExampleState>>, mut next_state: ResMut<NextState<ExampleState>>) {
    if state.get() == &ExampleState::State1 {
        info!("changing state");
        next_state.set(ExampleState::State2);
    }
}

This code causes app to panic when using the main branch of bevy_ecs_tilemap + bevy 0.12

This code does not cause app to panic when targeting bevy 0.11.3 and bevy_ecs_tilemap 0.11.0

This code does not panic if SpriteBundle is spawned with a texture.

panic occurs here in bevy_render:

let receiver = world.get_resource::<RenderToMainAppReceiver>().unwrap();
receiver.0.recv().await.unwrap()

attempting to unwrap recv().await.unwrap() fails