Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 43976)
+++ channels/chan_sip.c	(working copy)
@@ -6864,6 +6864,8 @@
 	transfercontext = pbx_builtin_getvar_helper(sip_pvt->owner, "TRANSFER_CONTEXT");
 	if (ast_strlen_zero(transfercontext))
 		transfercontext = sip_pvt->context;
+	else
+		strcpy(sip_pvt->context, transfercontext);
 
 	if (sip_debug_test_pvt(sip_pvt)) {
 		ast_verbose("Transfer to %s in %s\n", refer_to, transfercontext);