diff --git a/example/main/example_backend_nacm.c b/example/main/example_backend_nacm.c
index 8258b372..77c1f5bd 100644
--- a/example/main/example_backend_nacm.c
+++ b/example/main/example_backend_nacm.c
@@ -100,11 +100,19 @@ nacm_validate(clixon_handle    h,
     if (_transaction_log)
         transaction_log(h, td, LOG_NOTICE, __FUNCTION__);
     if (_validate_fail_xpath){
-        if (_validate_fail_toggle==0 &&
-            xpath_first(transaction_target(td), NULL, "%s", _validate_fail_xpath)){
-            _validate_fail_toggle = 1; /* toggle if triggered */
-            clixon_err(OE_XML, 0, "User error");
-            return -1; /* induce fail */
+        if (xpath_first(transaction_target(td), NULL, "%s", _validate_fail_xpath)) {
+            if (_validate_fail_toggle==0) {
+                _validate_fail_toggle = 1; /* toggle if triggered */
+                clixon_err(OE_XML, 0, "User error");
+                return -1; /* induce fail */
+            } else if (_validate_fail_toggle==2) {
+                _validate_fail_toggle = 0; /* toggle if triggered */
+                clixon_plugin_rpc_err(h, NULL,
+                                      "application", "test_error_tag",
+                                      "test_error_info", "error",
+                                      "test_error_data %d", 1234);
+                return -1; /* induce fail */
+            }
         }
     }
     return 0;
@@ -130,7 +138,7 @@ nacm_commit(clixon_handle    h,
     if (_validate_fail_xpath){
         if (_validate_fail_toggle==1 &&
             xpath_first(transaction_target(td), NULL, "%s", _validate_fail_xpath)){
-            _validate_fail_toggle = 0; /* toggle if triggered */
+            _validate_fail_toggle = 2; /* toggle if triggered */
             clixon_err(OE_XML, 0, "User error");
             return -1; /* induce fail */
         }
diff --git a/test/test_transaction.sh b/test/test_transaction.sh
index 1745d9ca..7837a424 100755
--- a/test/test_transaction.sh
+++ b/test/test_transaction.sh
@@ -11,7 +11,8 @@
 # 4. Validate user-error (invalidation by user callback)
 # 5. Commit user-error (invalidation by user callback)
 # -- to here only basic callback tests (that they occur). Below transaction data
-# 6. Detailed transaction vector add/del/change tests
+# 6. Validate user-error with plugin_rpc_err (invalidation by user callback)
+# 7. Detailed transaction vector add/del/change tests
 # For the last test, the yang is a list with three members, so that you can do
 # add/delete/change in a single go.
 # The user-error uses a trick feature in the example nacm plugin which is started
@@ -277,7 +278,34 @@ for op in abort; do
     let line++
 done
 
-# 6. Detailed transaction vector add/del/change tests
+# 6. Validate only user-error with plugin_rpc_err (invalidation by user callback)
+# XXX Note Commit user-error must immediately preceede this due to toggling
+# in nacm/transaction example test module
+let nr++
+new "6. Validate user-error with plugin_rpc_err ($errnr is invalid)"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><x xmlns='urn:example:clixon'><y><a>$errnr</a><c>99</c></y></x></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+new "Validate user-error validate (should fail)"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><validate><source><candidate/></source></validate></rpc>" "" "<rpc-reply $DEFAULTNS><rpc-error><error-type>application</error-type><error-tag>test_error_tag</error-tag><error-severity>error</error-severity><error-info>test_error_info</error-info><error-message>test_error_data 1234</error-message></rpc-error></rpc-reply>"
+
+new "Validate user-error discard-changes"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><discard-changes/></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
+
+for op in begin validate; do
+    checklog "$nr main_$op add: <y><a>$errnr</a><c>99</c></y>" $line
+    let line++
+    checklog "$nr nacm_$op add: <y><a>$errnr</a><c>99</c></y>" $line
+    let line++
+done
+# No error message here, don't increment line.
+for op in abort; do
+    checklog "$nr main_$op add: <y><a>$errnr</a><c>99</c></y>" $line
+    let line++
+    checklog "$nr nacm_$op add: <y><a>$errnr</a><c>99</c></y>" $line
+    let line++
+done
+
+# 7. Detailed transaction vector add/del/change tests
 let nr++
 let base=nr
 new "Add base <a>$base entry"
@@ -289,7 +317,7 @@ expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS>
 let line+=12
 
 let nr++
-new "6. netconf mixed change: change b, del c, add d"
+new "7. netconf mixed change: change b, del c, add d"
 expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><x xmlns='urn:example:clixon'><y><a>$base</a><b>42</b><d>0</d></y></x></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
 
 new "netconf commit change"
@@ -325,7 +353,7 @@ let line+=12
 
 # Variant check that only b,c
 let nr++
-new "7. netconf insert b,c between end-points"
+new "8. netconf insert b,c between end-points"
 expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><x xmlns='urn:example:clixon'><y><a>$base</a><b>1</b><c>1</c></y></x></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
 
 new "netconf commit base"
@@ -339,7 +367,7 @@ for op in begin validate complete commit commit_done end; do
     let line++
 done
 
-new "8. Choice"
+new "9. Choice"
 expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><x xmlns='urn:example:clixon'><first>true</first></x></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
 
 new "netconf commit same"
@@ -374,7 +402,7 @@ let line++
 checklog "$nr nacm_end add: <second>true</second>" $line
 let line++
 
-new "9. Choice/case with empty type"
+new "10. Choice/case with empty type"
 expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><x xmlns='urn:example:clixon'><aaa/></x></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
 
 new "netconf commit first"
@@ -411,7 +439,7 @@ let line++
 
 #---------------------------------------------
 
-new "10. Choice/case with anydata"
+new "11. Choice/case with anydata"
 expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><x xmlns='urn:example:clixon'><ddd><foo>a</foo></ddd></x></config></edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
 
 new "netconf commit first"