diff --git a/compiler/CompileContext.js b/compiler/CompileContext.js
index a1d8a3429..e8cf087fe 100644
--- a/compiler/CompileContext.js
+++ b/compiler/CompileContext.js
@@ -267,6 +267,10 @@ class CompileContext {
             let attrDef = taglibLookup.getAttribute(tagName, attrName);
             if (!attrDef) {
                 if (tagDef) {
+                    if (node.removeAttribute) {
+                        node.removeAttribute(attrName);
+                    }
+
                     // var isAttrForTaglib = compiler.taglibs.isTaglib(attrUri);
                     //Tag doesn't allow dynamic attributes
                     this.addError({
diff --git a/compiler/ast/CustomTag.js b/compiler/ast/CustomTag.js
index 0f55b7946..c8f3ab85e 100644
--- a/compiler/ast/CustomTag.js
+++ b/compiler/ast/CustomTag.js
@@ -131,6 +131,7 @@ function buildInputProps(el, context) {
         var attrDef = attr.def || context.taglibLookup.getAttribute(el.tagName, attr.name);
 
         if (!attrDef) {
+            context.addError(el, 'Unsupported attribute of "' + attrName + '" found on the <' + el.tagName + '> custom tag.');
             return; // Skip over attributes that are not supported
         }