diff --git a/infer/src/biabduction/SymExecBlocks.ml b/infer/src/biabduction/SymExecBlocks.ml
index 4ed8ddbbd..25da5c64d 100644
--- a/infer/src/biabduction/SymExecBlocks.ml
+++ b/infer/src/biabduction/SymExecBlocks.ml
@@ -38,7 +38,7 @@ let get_extended_args_for_method_with_block_analysis act_params =
             in
             append_no_duplicates_vars all_args captured
         | _ ->
-            append_no_duplicates_vars all_args [act_param] )
+            List.append all_args [act_param] )
   in
   List.map ~f:(fun (exp, _, typ) -> (exp, typ)) args_and_captured
 
diff --git a/infer/tests/codetoanalyze/objc/errors/Makefile b/infer/tests/codetoanalyze/objc/errors/Makefile
index 9276073ea..68a37bddd 100644
--- a/infer/tests/codetoanalyze/objc/errors/Makefile
+++ b/infer/tests/codetoanalyze/objc/errors/Makefile
@@ -74,6 +74,7 @@ SOURCES_BUCKET_ALL = \
   returnstmt/return_npe_test.m \
   shared/assertions/NSAssert_example.m \
   shared/block/BlockVar.m \
+  shared/block/AnonymousBlock.m \
   shared/block/block.m \
   shared/block/block_no_args.m \
   shared/block/block_release.m \
diff --git a/infer/tests/codetoanalyze/objc/shared/block/AnonymousBlock.m b/infer/tests/codetoanalyze/objc/shared/block/AnonymousBlock.m
new file mode 100644
index 000000000..7463734bf
--- /dev/null
+++ b/infer/tests/codetoanalyze/objc/shared/block/AnonymousBlock.m
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2018-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <Foundation/Foundation.h>
+
+void anonBlock() {
+  CFRunLoopObserverRef observer = CFRunLoopObserverCreateWithHandler(
+      NULL,
+      kCFRunLoopBeforeWaiting,
+      NO,
+      UINT_MAX,
+      ^(CFRunLoopObserverRef obs, CFRunLoopActivity activity) {
+        CFRelease(obs);
+      });
+  CFRunLoopAddObserver(CFRunLoopGetMain(), observer, kCFRunLoopCommonModes);
+}
+
+void blockVar() {
+  // This case doesnt fail like the one above (with the anonymous block) used
+  // to. That's because using the block variable populates the args list
+  // differently thus avoiding the dupliate.
+  void (^bvar)(CFRunLoopObserverRef observer, CFRunLoopActivity activity) =
+      ^(CFRunLoopObserverRef obs, CFRunLoopActivity activity) {
+        CFRelease(obs);
+      };
+
+  CFRunLoopObserverRef observer = CFRunLoopObserverCreateWithHandler(
+      NULL, kCFRunLoopBeforeWaiting, NO, UINT_MAX, bvar);
+  CFRunLoopAddObserver(CFRunLoopGetMain(), observer, kCFRunLoopCommonModes);
+}