Update UniqueEntity.rst

Author: wkania

reference/constraints/UniqueEntity.rst

@@ -406,8 +406,9 @@ fields configured in the ``fields`` option). The method should return a
 
     This constraint does not support Doctrine types such as ``simple_array``,
     ``json``, or ``jsonb``, nor does it handle association mappings like
-    ``One-To-Many`` and ``Many-To-Many`` relationships. To perform uniqueness
-    checks on such fields, you must define a custom ``repositoryMethod`` that
+    ``One-To-Many`` and ``Many-To-Many`` relationships. It may also not work
+    correctly with custom Doctrine types. To perform uniqueness checks on
+    such fields, you must define a custom ``repositoryMethod`` that
     implements the desired logic.
 
 .. _`race conditions`: https://en.wikipedia.org/wiki/Race_condition