diff --git a/src/amplitude_experiment/cohort/cohort_loader.py b/src/amplitude_experiment/cohort/cohort_loader.py
index e951cd9..e5d6639 100644
--- a/src/amplitude_experiment/cohort/cohort_loader.py
+++ b/src/amplitude_experiment/cohort/cohort_loader.py
@@ -39,16 +39,20 @@ def download_cohort(self, cohort_id: str) -> Cohort:
     def update_stored_cohorts(self) -> Future:
         def update_task():
             errors = []
-            try:
-                futures = [self.executor.submit(self.__load_cohort_internal, cohort_id) for cohort_id in self.cohort_storage.get_cohort_ids()]
+            cohort_ids = self.cohort_storage.get_cohort_ids()
 
-                for future, cohort_id in zip(as_completed(futures), self.cohort_storage.get_cohort_ids()):
-                    try:
-                        future.result()
-                    except Exception as e:
-                        errors.append((cohort_id, e))
-            except Exception as e:
-                errors.append(e)
+            futures = []
+            with self.lock_jobs:
+                for cohort_id in cohort_ids:
+                    future = self.load_cohort(cohort_id)
+                    futures.append(future)
+
+            for future in as_completed(futures):
+                cohort_id = next(c_id for c_id, f in self.jobs.items() if f == future)
+                try:
+                    future.result()
+                except Exception as e:
+                    errors.append((cohort_id, e))
 
             if errors:
                 raise CohortUpdateException(errors)