diff --git a/src/core/coap/coap.cpp b/src/core/coap/coap.cpp
index 6c4bce76d..726c2f483 100644
--- a/src/core/coap/coap.cpp
+++ b/src/core/coap/coap.cpp
@@ -189,7 +189,7 @@ ThreadError Coap::SendMessage(Message &aMessage, const Ip6::MessageInfo &aMessag
         // Create a copy of entire message and enqueue it.
         copyLength = aMessage.GetLength();
     }
-    else if (header.IsNonConfirmable() && header.IsRequest() && (aHandler != NULL))
+    else if (header.IsNonConfirmable() && (aHandler != NULL))
     {
         // As we do not retransmit non confirmable messages, create a copy of header only, for token information.
         copyLength = header.GetLength();
@@ -466,7 +466,9 @@ Message *Coap::FindRelatedRequest(const Header &aResponseHeader, const Ip6::Mess
              aCoapMetadata.mDestinationAddress.IsAnycastRoutingLocator()) &&
             (aCoapMetadata.mDestinationPort == aMessageInfo.GetPeerPort()))
         {
-            assert(aRequestHeader.FromMessage(*message, sizeof(CoapMetadata)) == kThreadError_None);
+            // FromMessage can return kThreadError_Parse if only partial message was stored (header only),
+            // but payload marker is present. Assume, that stored messages are always valid.
+            aRequestHeader.FromMessage(*message, sizeof(CoapMetadata));
 
             switch (aResponseHeader.GetType())
             {