diff --git a/modules/userId/eids.js b/modules/userId/eids.js
index aad570f20df..e5f7e3b8fb2 100644
--- a/modules/userId/eids.js
+++ b/modules/userId/eids.js
@@ -1,4 +1,4 @@
-import {deepAccess, isFn, isPlainObject, isStr} from '../../src/utils.js';
+import {deepAccess, deepClone, isFn, isPlainObject, isStr} from '../../src/utils.js';
 
 export const EID_CONFIG = new Map();
 
@@ -45,7 +45,7 @@ export function createEidsArray(bidRequestUserId) {
 
   Object.entries(bidRequestUserId).forEach(([name, values]) => {
     values = Array.isArray(values) ? values : [values];
-    const eids = name === 'pubProvidedId' ? values : values.map(value => createEidObject(value, name));
+    const eids = name === 'pubProvidedId' ? deepClone(values) : values.map(value => createEidObject(value, name));
     eids.filter(eid => eid != null).forEach(collect);
   })
   return Object.values(allEids);
diff --git a/test/spec/modules/userId_spec.js b/test/spec/modules/userId_spec.js
index 17a865796a2..18f49f4943e 100644
--- a/test/spec/modules/userId_spec.js
+++ b/test/spec/modules/userId_spec.js
@@ -448,7 +448,25 @@ describe('User ID', function () {
             ]
           }
         ])
-      })
+      });
+
+      it('when merging with pubCommonId, should not alter its eids', () => {
+        const uid = {
+          pubProvidedId: [
+            {
+              source: 'mock1Source',
+              uids: [
+                {id: 'uid2'}
+              ]
+            }
+          ],
+          mockId1: 'uid1',
+        };
+        const eids = createEidsArray(uid);
+        expect(eids).to.have.length(1);
+        expect(eids[0].uids.map(u => u.id)).to.have.members(['uid1', 'uid2']);
+        expect(uid.pubProvidedId[0].uids).to.eql([{id: 'uid2'}]);
+      });
     })
 
     it('pbjs.getUserIds', function (done) {