diff --git a/documentation/KnownProblems.txt b/documentation/KnownProblems.txt
index 3818490492fe99afd3a4400ff314658ed92e2644..644be776413eccc1c91a4aadfecfdc811dfe79ec 100644
--- a/documentation/KnownProblems.txt
+++ b/documentation/KnownProblems.txt
@@ -1,6 +1,18 @@
 Known Problems
 ==============
 
+.. _Known_Problems_2.1.5:
+
+Known Problems in Release 2.1.5
+-------------------------------
+
+* Using pvPutComplete or pvGetComplete inside a when-clause may
+  result in a deadlock: the state set forever waits for the
+  completion even though the callback arrived.
+
+  Note: this Problem is present at least since 2.0.12.
+
+
 .. _Known_Problems_2.1.4:
 
 Known Problems in Release 2.1.4
diff --git a/documentation/Notes.txt b/documentation/Notes.txt
index 29dcc74b49cf6a53e33d1703b742c242aa6953d0..b39a8eb25188f271a63a43fed62aad11179ac389 100644
--- a/documentation/Notes.txt
+++ b/documentation/Notes.txt
@@ -6,6 +6,8 @@ Release Notes
 Release 2.1.5
 -------------
 
+:ref:`Known_Problems_2.1.5`
+
 * fixed two bugs in pvAssign:
 
   - after an initially unassigned variable gets assigned using