diff --git a/plugins/tasks/tasks-core/src/com/intellij/tasks/impl/LocalTaskImpl.java b/plugins/tasks/tasks-core/src/com/intellij/tasks/impl/LocalTaskImpl.java
index b8253b569431..393c9fe76021 100644
--- a/plugins/tasks/tasks-core/src/com/intellij/tasks/impl/LocalTaskImpl.java
+++ b/plugins/tasks/tasks-core/src/com/intellij/tasks/impl/LocalTaskImpl.java
@@ -211,6 +211,7 @@ public class LocalTaskImpl extends LocalTask {
     return myChangeLists;
   }
 
+  // for serialization
   public void setChangeLists(List<ChangeListInfo> changeLists) {
     myChangeLists = changeLists;
   }
diff --git a/plugins/tasks/tasks-core/src/com/intellij/tasks/impl/TaskManagerImpl.java b/plugins/tasks/tasks-core/src/com/intellij/tasks/impl/TaskManagerImpl.java
index 9dc54791e98f..084ea4bfdb7d 100644
--- a/plugins/tasks/tasks-core/src/com/intellij/tasks/impl/TaskManagerImpl.java
+++ b/plugins/tasks/tasks-core/src/com/intellij/tasks/impl/TaskManagerImpl.java
@@ -885,7 +885,7 @@ public class TaskManagerImpl extends TaskManager implements ProjectComponent, Pe
   @Override
   public LocalTask getAssociatedTask(@NotNull LocalChangeList list) {
     for (LocalTask task : getLocalTasks()) {
-      for (ChangeListInfo changeListInfo : task.getChangeLists()) {
+      for (ChangeListInfo changeListInfo : new ArrayList<>(task.getChangeLists())) {
         if (changeListInfo.id.equals(list.getId())) {
           return task;
         }