diff --git a/change/@microsoft-fast-element-74afe8a2-ec05-4780-8034-5c2ea436d82e.json b/change/@microsoft-fast-element-74afe8a2-ec05-4780-8034-5c2ea436d82e.json
new file mode 100644
index 00000000000..57853f391d7
--- /dev/null
+++ b/change/@microsoft-fast-element-74afe8a2-ec05-4780-8034-5c2ea436d82e.json
@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Moves handleEvent from a class property into a closure in children.ts to remove non-standard observer.target property assignment",
+  "packageName": "@microsoft/fast-element",
+  "email": "email not defined",
+  "dependentChangeType": "none"
+}
diff --git a/packages/fast-element/src/templating/children.ts b/packages/fast-element/src/templating/children.ts
index dce1c524d95..eea09735dad 100644
--- a/packages/fast-element/src/templating/children.ts
+++ b/packages/fast-element/src/templating/children.ts
@@ -65,12 +65,14 @@ export class ChildrenDirective extends NodeObservationDirective<ChildrenDirectiv
         let observer = target[this.observerProperty];
 
         if (!observer) {
-            observer = new MutationObserver(this.handleEvent);
+            const handleEvent = (mutations, observer) => {
+                this.updateTarget(this.getSource(target), this.computeNodes(target));
+            };
+            observer = new MutationObserver(handleEvent);
             observer.toJSON = noop;
             target[this.observerProperty] = observer;
         }
 
-        observer.target = target;
         observer.observe(target, this.options);
     }
 
@@ -80,7 +82,6 @@ export class ChildrenDirective extends NodeObservationDirective<ChildrenDirectiv
      */
     disconnect(target: any): void {
         const observer = target[this.observerProperty];
-        observer.target = null;
         observer.disconnect();
     }
 
@@ -95,11 +96,6 @@ export class ChildrenDirective extends NodeObservationDirective<ChildrenDirectiv
 
         return Array.from(target.childNodes);
     }
-
-    private handleEvent = (mutations: MutationRecord[], observer: any): void => {
-        const target = observer.target;
-        this.updateTarget(this.getSource(target), this.computeNodes(target));
-    };
 }
 
 HTMLDirective.define(ChildrenDirective);