diff --git a/check_api/src/main/java/com/google/errorprone/ErrorProneFlags.java b/check_api/src/main/java/com/google/errorprone/ErrorProneFlags.java
index 48dada29b78..09b3d18b534 100644
--- a/check_api/src/main/java/com/google/errorprone/ErrorProneFlags.java
+++ b/check_api/src/main/java/com/google/errorprone/ErrorProneFlags.java
@@ -63,7 +63,7 @@ private ErrorProneFlags(ImmutableMap<String, String> flagsMap) {
   }
 
   public ImmutableMap<String, String> getFlagsMap() {
-    return ImmutableMap.copyOf(flagsMap);
+    return flagsMap;
   }
 
   /**