diff --git a/Source/Classes/Pull/PullOperation.swift b/Source/Classes/Pull/PullOperation.swift
index 56810d0..1bd52bd 100644
--- a/Source/Classes/Pull/PullOperation.swift
+++ b/Source/Classes/Pull/PullOperation.swift
@@ -35,7 +35,9 @@ public class PullOperation: Operation {
         let convertOperation = RecordToCoreDataOperation(parentContext: context, record: record)
         convertOperation.errorBlock = { self.errorBlock?($0) }
         convertOperation.completionBlock = {
-            self.objectsWithMissingReferences.append(convertOperation.missingObjectsPerEntities)
+            context.performAndWait {
+                self.objectsWithMissingReferences.append(convertOperation.missingObjectsPerEntities)
+            }
         }
         self.queue.addOperation(convertOperation)
     }