diff --git a/java/google/registry/model/EppResourceUtils.java b/java/google/registry/model/EppResourceUtils.java
index 24a8cf477..65a5a891e 100644
--- a/java/google/registry/model/EppResourceUtils.java
+++ b/java/google/registry/model/EppResourceUtils.java
@@ -347,12 +347,10 @@ public final class EppResourceUtils {
   public static List<Key<DomainBase>> queryDomainsUsingResource(
       Class<? extends EppResource> clazz, Key<? extends EppResource> key, DateTime now, int limit) {
     checkArgument(ContactResource.class.equals(clazz) || HostResource.class.equals(clazz));
-    return ofy().load().type(DomainBase.class)
-        .filter(
-            clazz.equals(ContactResource.class)
-                ? "allContacts.contactId.linked"
-                : "nameservers.linked",
-            key)
+    return ofy()
+        .load()
+        .type(DomainBase.class)
+        .filter(clazz.equals(ContactResource.class) ? "allContacts.contact" : "nsHosts", key)
         .filter("deletionTime >", now)
         .limit(limit)
         .keys()
diff --git a/java/google/registry/model/domain/DesignatedContact.java b/java/google/registry/model/domain/DesignatedContact.java
index 0712f42cf..96c3e8003 100644
--- a/java/google/registry/model/domain/DesignatedContact.java
+++ b/java/google/registry/model/domain/DesignatedContact.java
@@ -72,6 +72,6 @@ public class DesignatedContact extends ImmutableObject {
   }
 
   public Key<ContactResource> getContactKey() {
-    return contactId.getLinked();
+    return contact;
   }
 }
diff --git a/java/google/registry/model/domain/DomainBase.java b/java/google/registry/model/domain/DomainBase.java
index 9c37eebda..987618974 100644
--- a/java/google/registry/model/domain/DomainBase.java
+++ b/java/google/registry/model/domain/DomainBase.java
@@ -183,11 +183,7 @@ public abstract class DomainBase extends EppResource {
   }
 
   public ImmutableSet<Key<HostResource>> getNameservers() {
-    ImmutableSet.Builder<Key<HostResource>> builder = new ImmutableSet.Builder<>();
-    for (ReferenceUnion<HostResource> union : nullToEmptyImmutableCopy(nameservers)) {
-      builder.add(union.getLinked());
-    }
-    return builder.build();
+    return nullToEmptyImmutableCopy(nsHosts);
   }
 
   /** Loads and returns the fully qualified host names of all linked nameservers. */
@@ -242,13 +238,13 @@ public abstract class DomainBase extends EppResource {
   @OnSave
   void dualSaveReferenceUnions() {
     for (DesignatedContact contact : nullToEmptyImmutableCopy(allContacts)) {
-      contact.contact = contact.contactId.getLinked();
+      contact.contactId = ReferenceUnion.create(contact.contact);
     }
-    ImmutableSet.Builder<Key<HostResource>> hostKeys = new ImmutableSet.Builder<>();
-    for (ReferenceUnion<HostResource> refUnion : nullToEmptyImmutableCopy(nameservers)) {
-      hostKeys.add(refUnion.getLinked());
+    ImmutableSet.Builder<ReferenceUnion<HostResource>> hosts = new ImmutableSet.Builder<>();
+    for (Key<HostResource> hostKey : nullToEmptyImmutableCopy(nsHosts)) {
+      hosts.add(ReferenceUnion.create(hostKey));
     }
-    nsHosts = hostKeys.build();
+    nameservers = hosts.build();
   }
 
   /** Predicate to determine if a given {@link DesignatedContact} is the registrant. */
@@ -307,11 +303,7 @@ public abstract class DomainBase extends EppResource {
     }
 
     public B setNameservers(ImmutableSet<Key<HostResource>> nameservers) {
-      ImmutableSet.Builder<ReferenceUnion<HostResource>> builder = new ImmutableSet.Builder<>();
-      for (Key<HostResource> key : nullToEmpty(nameservers)) {
-        builder.add(ReferenceUnion.create(key));
-      }
-      getInstance().nameservers = builder.build();
+      getInstance().nsHosts = nameservers;
       return thisCastToDerived();
     }
 
diff --git a/java/google/registry/rdap/RdapDomainSearchAction.java b/java/google/registry/rdap/RdapDomainSearchAction.java
index 15b2144bd..fb8912c38 100644
--- a/java/google/registry/rdap/RdapDomainSearchAction.java
+++ b/java/google/registry/rdap/RdapDomainSearchAction.java
@@ -269,7 +269,7 @@ public class RdapDomainSearchAction extends RdapActionBase {
     for (List<Key<HostResource>> chunk : Iterables.partition(hostKeys, 30)) {
       for (DomainResource domain : ofy().load()
           .type(DomainResource.class)
-          .filter("nameservers.linked in", chunk)
+          .filter("nsHosts in", chunk)
           .filter("deletionTime >", now)
           .limit(rdapResultSetMaxSize + 1)) {
         if (!domains.contains(domain)) {
diff --git a/javatests/google/registry/model/domain/DomainApplicationTest.java b/javatests/google/registry/model/domain/DomainApplicationTest.java
index c76997ff2..cbe4d2c0c 100644
--- a/javatests/google/registry/model/domain/DomainApplicationTest.java
+++ b/javatests/google/registry/model/domain/DomainApplicationTest.java
@@ -145,16 +145,16 @@ public class DomainApplicationTest extends EntityTestCase {
 
   @Test
   public void testEmptySetsAndArraysBecomeNull() {
-    assertThat(emptyBuilder().setNameservers(null).build().nameservers).isNull();
+    assertThat(emptyBuilder().setNameservers(null).build().nsHosts).isNull();
     assertThat(emptyBuilder()
         .setNameservers(ImmutableSet.<Key<HostResource>>of())
         .build()
-        .nameservers)
+        .nsHosts)
             .isNull();
     assertThat(emptyBuilder()
         .setNameservers(ImmutableSet.of(Key.create(newHostResource("foo.example.tld"))))
         .build()
-        .nameservers)
+        .nsHosts)
             .isNotNull();
     // This behavior should also hold true for ImmutableObjects nested in collections.
     assertThat(emptyBuilder()
diff --git a/javatests/google/registry/model/domain/DomainResourceTest.java b/javatests/google/registry/model/domain/DomainResourceTest.java
index 3d7bfd4bd..e15f8d8d3 100644
--- a/javatests/google/registry/model/domain/DomainResourceTest.java
+++ b/javatests/google/registry/model/domain/DomainResourceTest.java
@@ -207,13 +207,13 @@ public class DomainResourceTest extends EntityTestCase {
   @Test
   public void testEmptySetsAndArraysBecomeNull() {
     assertThat(newDomainResource("example.com").asBuilder()
-        .setNameservers(null).build().nameservers).isNull();
+        .setNameservers(null).build().nsHosts).isNull();
     assertThat(newDomainResource("example.com").asBuilder()
-        .setNameservers(ImmutableSet.<Key<HostResource>>of()).build().nameservers)
+        .setNameservers(ImmutableSet.<Key<HostResource>>of()).build().nsHosts)
             .isNull();
     assertThat(newDomainResource("example.com").asBuilder()
         .setNameservers(ImmutableSet.of(Key.create(newHostResource("foo.example.tld"))))
-            .build().nameservers)
+            .build().nsHosts)
                 .isNotNull();
     // This behavior should also hold true for ImmutableObjects nested in collections.
     assertThat(newDomainResource("example.com").asBuilder()
@@ -462,21 +462,22 @@ public class DomainResourceTest extends EntityTestCase {
   public void testDualSavingOfDesignatedContact() {
     ContactResource contact = persistActiveContact("time1006");
     DesignatedContact designatedContact = new DesignatedContact();
-    designatedContact.contactId = ReferenceUnion.create(Key.create(contact));
+    designatedContact.contact = Key.create(contact);
     designatedContact.type = Type.ADMIN;
     DomainResource domainWithContact =
         domain.asBuilder().setContacts(ImmutableSet.of(designatedContact)).build();
-    assertThat(getOnlyElement(domainWithContact.getContacts()).contact).isNull();
+    assertThat(getOnlyElement(domainWithContact.getContacts()).contactId).isNull();
     DomainResource reloadedDomain = persistResource(domainWithContact);
-    assertThat(getOnlyElement(reloadedDomain.getContacts()).contact).isEqualTo(Key.create(contact));
+    assertThat(getOnlyElement(reloadedDomain.getContacts()).contactId)
+        .isEqualTo(ReferenceUnion.create(Key.create(contact)));
   }
 
   @Test
   public void testDualSavingOfNameservers() {
     HostResource host = persistActiveHost("zzz.xxx.yyy");
     DomainResource domain = newDomainResource("python-django-unchained.com", host);
-    assertThat(domain.nsHosts).isNull();
+    assertThat(domain.nameservers).isNull();
     DomainResource djangoReloaded = persistResource(domain);
-    assertThat(djangoReloaded.nsHosts).containsExactly(Key.create(host));
+    assertThat(djangoReloaded.nameservers).containsExactly(ReferenceUnion.create(Key.create(host)));
   }
 }