diff --git a/datahub-web-react/src/app/entity/shared/siblingUtils.ts b/datahub-web-react/src/app/entity/shared/siblingUtils.ts
index 93c08022f47a4..f280716922d89 100644
--- a/datahub-web-react/src/app/entity/shared/siblingUtils.ts
+++ b/datahub-web-react/src/app/entity/shared/siblingUtils.ts
@@ -43,20 +43,20 @@ const combineMerge = (target, source, options) => {
 
 const customMerge = (isPrimary, key) => {
     if (key === 'upstream' || key === 'downstream') {
-        return (a, _) => a;
+        return (_secondary, primary) => primary;
     }
     if (key === 'platform') {
-        return (a, b) => (isPrimary ? b : a);
+        return (secondary, primary) => (isPrimary ? primary : secondary);
     }
     if (key === 'tags' || key === 'terms' || key === 'assertions') {
-        return (a, b) => {
-            return merge(a, b, {
+        return (secondary, primary) => {
+            return merge(secondary, primary, {
                 customMerge: customMerge.bind({}, isPrimary),
             });
         };
     }
-    return (a, b) => {
-        return merge(a, b, {
+    return (secondary, primary) => {
+        return merge(secondary, primary, {
             arrayMerge: combineMerge,
             customMerge: customMerge.bind({}, isPrimary),
         });