diff --git a/ignite-template.js b/ignite-template.js
index c2da413..9f18f92 100644
--- a/ignite-template.js
+++ b/ignite-template.js
@@ -1224,7 +1224,12 @@ class IgniteTemplate {
                 }
             } else {
                 this._attributes["disabled"] = null;
-                this._classes.splice(this._classes.indexOf("disabled"), 1);
+
+                var disabledIndex = this._classes.indexOf("disabled");
+
+                if (disabledIndex >= 0) {
+                    this._classes.splice(disabledIndex, 1);
+                }
 
                 if (this.element) {
                     this.element.removeAttribute("disabled");
@@ -1660,10 +1665,20 @@ class IgniteTemplate {
         }
 
         //Remove the old values from the template, but only remove one copy.
-        oldClasses.forEach((cl) => this._classes.splice(this._classes.indexOf(cl), 1));
+        oldClasses.forEach((cl) => {
+            var clIndex = this._classes.indexOf(cl);
+            if (clIndex >= 0) {
+                this._classes.splice(clIndex, 1);
+            }
+        });
 
         //Add the new classes to the template.
-        newClasses.forEach((cl) => this._classes.push(cl));
+        newClasses.forEach((cl) => {
+            var clIndex = this._classes.indexOf(cl);
+            if (clIndex < 0) {
+                this._classes.push(cl);
+            }
+        });
 
         //For any classes that are missing on the element, add them. If we have duplicates this
         //can happen.