fix

src/entities/tasks/executor.rs

@@ -33,8 +33,11 @@ pub fn task_executor_system(
     mut completed_writer: MessageWriter<TaskCompleted>,
     mut failed_writer: MessageWriter<TaskFailed>,
 ) {
-    let Ok(mut rng) = rng_q.single_mut() else {
-        return;
+    // Get mutable access to the single GlobalRng entity
+    // This must be done once per frame, not per entity
+    let mut rng = match rng_q.single_mut() {
+        Ok(r) => r,
+        Err(_) => return, // No GlobalRng entity exists yet
     };
 
     for (entity, mut queue, mut state, mut ambulatory, transform) in query.iter_mut() {