Add known issue of Apache AGE to the readme.

README.md

@@ -366,6 +366,11 @@ For production level scenarios you will most likely want to leverage an enterpri
   SET search_path = ag_catalog, "$user", public;
   CREATE INDEX idx_entity ON dickens."Entity" USING gin (agtype_access_operator(properties, '"node_id"'));
   ```
+* Known issue of the Apache AGE: The released versions got below issue:
+  > You might find that the properties of the nodes/edges are empty.
+  > It is a known issue of the release version: https://github.com/apache/age/pull/1721
+  > You can Compile the AGE from source code and fix it.
+
 
 ### Insert Custom KG