diff --git a/packages/redux-devtools-core/src/app/utils/stringifyJSON.js b/packages/redux-devtools-core/src/app/utils/stringifyJSON.js
index 67c8187d..d3191612 100644
--- a/packages/redux-devtools-core/src/app/utils/stringifyJSON.js
+++ b/packages/redux-devtools-core/src/app/utils/stringifyJSON.js
@@ -4,9 +4,10 @@ import { DATA_TYPE_KEY, DATA_REF_KEY } from '../constants/dataTypes';
 function replacer(key, value) {
   if (typeof value === 'object' && value !== null && DATA_TYPE_KEY in value) {
     const __serializedType__ = value[DATA_TYPE_KEY];
-    delete value[DATA_TYPE_KEY]; // eslint-disable-line no-param-reassign
-    const r = { data: value, __serializedType__ };
-    if (DATA_REF_KEY in value) r.__serializedRef__ = value[DATA_REF_KEY];
+    const clone = { ...value };
+    delete clone[DATA_TYPE_KEY]; // eslint-disable-line no-param-reassign
+    const r = { data: clone, __serializedType__ };
+    if (DATA_REF_KEY in value) r.__serializedRef__ = clone[DATA_REF_KEY];
     return r;
   }
   return value;