diff --git a/docs/README.md b/docs/README.md
index 4315116f8..8b487b8cf 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -5,4 +5,13 @@
 1. Run ./bin/install-dependencies.sh
 2. Run ./bin/generate-docs.sh
 
-It will generate the documentation into the build directory of the checkout.
\ No newline at end of file
+It will generate the documentation into the build directory of the checkout.
+
+
+## Theme issues
+
+If you get a "Theme error", check if the `en/_theme` subdirectory is empty,
+in which case you will need to run:
+
+1. git submodule init
+2. git submodule update
diff --git a/docs/en/reference/transactions-and-concurrency.rst b/docs/en/reference/transactions-and-concurrency.rst
index 4dc18318e..c012d9049 100644
--- a/docs/en/reference/transactions-and-concurrency.rst
+++ b/docs/en/reference/transactions-and-concurrency.rst
@@ -98,6 +98,13 @@ functionally equivalent to the previously shown code looks as follows:
         $em->persist($user);
     });
 
+.. warning::
+
+    For historical reasons, ``EntityManager#transactional($func)`` will return
+    ``false`` whenever the return value of ``$func`` is loosely false.
+    Some examples of this include ``array()``, ``"0"``, ``""``, ``0``, and
+    ``null``.
+
 The difference between ``Connection#transactional($func)`` and
 ``EntityManager#transactional($func)`` is that the latter
 abstraction flushes the ``EntityManager`` prior to transaction