diff --git a/modules/adnuntiusBidAdapter.js b/modules/adnuntiusBidAdapter.js
index 6f3ed6eb5b6..a498d056513 100644
--- a/modules/adnuntiusBidAdapter.js
+++ b/modules/adnuntiusBidAdapter.js
@@ -63,7 +63,7 @@ const storageTool = (function () {
     }
 
     const updateVoidAuIds = function (currentVoidAuIds, auIdsAsString) {
-      const newAuIds = auIdsAsString ? auIdsAsString.split(';') : [];
+      const newAuIds = isStr(auIdsAsString) ? auIdsAsString.split(';') : [];
       const notNewExistingAuIds = currentVoidAuIds.filter(auIdObj => {
         return newAuIds.indexOf(auIdObj.value) < -1;
       }) || [];
@@ -83,7 +83,7 @@ const storageTool = (function () {
         }
       }
     }
-    const currentAuIds = updateVoidAuIds(metaAsObj.voidAuIds || [], apiResponse.voidAuIds || []);
+    const currentAuIds = updateVoidAuIds(metaAsObj.voidAuIds || [], apiResponse.voidAuIds);
     if (currentAuIds.length > 0) {
       metaAsObj.voidAuIds = { value: currentAuIds };
     }
diff --git a/test/spec/modules/adnuntiusBidAdapter_spec.js b/test/spec/modules/adnuntiusBidAdapter_spec.js
index e4902ca11b2..e109ca1829c 100644
--- a/test/spec/modules/adnuntiusBidAdapter_spec.js
+++ b/test/spec/modules/adnuntiusBidAdapter_spec.js
@@ -909,6 +909,7 @@ describe('adnuntiusBidAdapter', function() {
         ]
       };
       serverResponse.body.adUnits[0].deals = [];
+      delete serverResponse.body.metaData.voidAuIds; // test response with no voidAuIds
 
       const interpretedResponse = spec.interpretResponse(serverResponse, altBidder);
       expect(interpretedResponse).to.have.lengthOf(0);