diff --git a/packages/dom/src/prepare-dom.js b/packages/dom/src/prepare-dom.js
index 25a093219..52d1a0011 100644
--- a/packages/dom/src/prepare-dom.js
+++ b/packages/dom/src/prepare-dom.js
@@ -6,18 +6,13 @@ export function uid() {
 export function markElement(domElement, disableShadowDOM) {
   // Mark elements that are to be serialized later with a data attribute.
   if (['input', 'textarea', 'select', 'iframe', 'canvas', 'video', 'style'].includes(domElement.tagName?.toLowerCase())) {
-    if (!domElement.getAttribute('data-percy-element-id')) {
-      domElement.setAttribute('data-percy-element-id', uid());
-    }
+    domElement.setAttribute('data-percy-element-id', uid());
   }
 
   // add special marker for shadow host
   if (!disableShadowDOM && domElement.shadowRoot) {
     domElement.setAttribute('data-percy-shadow-host', '');
-
-    if (!domElement.getAttribute('data-percy-element-id')) {
-      domElement.setAttribute('data-percy-element-id', uid());
-    }
+    domElement.setAttribute('data-percy-element-id', uid());
   }
 }
 
diff --git a/packages/dom/test/serialize-inputs.test.js b/packages/dom/test/serialize-inputs.test.js
index da37f106a..156e0c10d 100644
--- a/packages/dom/test/serialize-inputs.test.js
+++ b/packages/dom/test/serialize-inputs.test.js
@@ -62,8 +62,10 @@ describe('serializeInputs', () => {
           option.selected = false;
         }
       });
-      cache[platform].dom = dom;
       cache[platform].$ = parseDOM(serializeDOM(), platform);
+      // save DOM, only after serializing it
+      // clone DOM, so that during next platform iteration, serializeDOM doesn't change current original DOM
+      cache[platform].dom = platform === 'shadow' ? dom : dom.cloneNode(true);
     });
     // interact with the inputs to update properties (does not update attributes)
   });
@@ -132,14 +134,6 @@ describe('serializeInputs', () => {
       expect(og).toEqual($('[data-percy-element-id]')[0].getAttribute('data-percy-element-id'));
     });
 
-    it(`${platform}: does not override previous guids when reserializing`, () => {
-      let getUid = () => dom.querySelector('[data-percy-element-id]').getAttribute('data-percy-element-id');
-      let first = getUid();
-
-      serializeDOM();
-      expect(getUid()).toEqual(first);
-    });
-
     it(`${platform}: does not mutate values in origial DOM`, () => {
       expect($('#name')[0].getAttribute('value')).toBe('Bob Boberson');
       expect(dom.querySelector('#name').getAttribute('value')).toBeNull();