Added known bug reference for experimental internal map.
diff --git a/include/json/config.h b/include/json/config.h
index 8e69b7a..6344729 100644
--- a/include/json/config.h
+++ b/include/json/config.h
@@ -16,7 +16,7 @@
 //#  define JSON_USE_CPPTL_SMALLMAP 1
 /// If defined, indicates that Json specific container should be used
 /// (hash table & simple deque container with customizable allocator).
-/// THIS FEATURE IS STILL EXPERIMENTAL!
+/// THIS FEATURE IS STILL EXPERIMENTAL! There is know bugs: See #3177332
 //#  define JSON_VALUE_USE_INTERNAL_MAP 1
 /// Force usage of standard new/malloc based allocator instead of memory pool based allocator.
 /// The memory pools allocator used optimization (initializing Value and ValueInternalLink