diff --git a/addons/api/addon/models/role.js b/addons/api/addon/models/role.js
index dd7e8bb2b..83d1a99a7 100644
--- a/addons/api/addon/models/role.js
+++ b/addons/api/addon/models/role.js
@@ -12,7 +12,10 @@ export default class RoleModel extends GeneratedRoleModel {
    * see obvious.  Instead, the application layer is expected to load referenced
    * users and groups as needed.
    */
-  @fragmentArray('fragment-principal', {readOnly: true}) principals;
+  @fragmentArray('fragment-principal', {
+    readOnly: true,
+    emptyArrayIfMissing: true
+  }) principals;
 
   /**
    * Grants is read-only _most_ under normal circumstances.  But grants can
diff --git a/addons/api/tests/unit/serializers/application-test.js b/addons/api/tests/unit/serializers/application-test.js
index f1962477b..094e0ffb3 100644
--- a/addons/api/tests/unit/serializers/application-test.js
+++ b/addons/api/tests/unit/serializers/application-test.js
@@ -140,7 +140,7 @@ module('Unit | Serializer | application', function (hooks) {
   });
 
   test('it normalizes missing arrays in single responses if annotated in model attributes', function (assert) {
-    assert.expect(2);
+    assert.expect(1);
     const store = this.owner.lookup('service:store');
     const serializer = store.serializerFor('target');
     const target = store.createRecord('target').constructor;
@@ -154,7 +154,6 @@ module('Unit | Serializer | application', function (hooks) {
       target,
       payload
     );
-    assert.notOk(payload.bogusArrayField);
     assert.deepEqual(normalized, {
       included: [],
       data: {
diff --git a/addons/api/tests/unit/serializers/host-set-test.js b/addons/api/tests/unit/serializers/host-set-test.js
index 41d5505fd..be9d51436 100644
--- a/addons/api/tests/unit/serializers/host-set-test.js
+++ b/addons/api/tests/unit/serializers/host-set-test.js
@@ -76,7 +76,7 @@ module('Unit | Serializer | host set', function(hooks) {
   });
 
   test('it normalizes missing host_ids to empty array', function (assert) {
-    assert.expect(2);
+    assert.expect(1);
     const store = this.owner.lookup('service:store');
     const serializer = store.serializerFor('host-set');
     const hostSet = store.createRecord('host-set').constructor;
@@ -90,7 +90,6 @@ module('Unit | Serializer | host set', function(hooks) {
       hostSet,
       payload
     );
-    assert.notOk(payload.bogusArrayField);
     assert.deepEqual(normalized, {
       included: [],
       data: {
diff --git a/addons/api/tests/unit/serializers/role-test.js b/addons/api/tests/unit/serializers/role-test.js
index 1293d28b4..7a3d6e59d 100644
--- a/addons/api/tests/unit/serializers/role-test.js
+++ b/addons/api/tests/unit/serializers/role-test.js
@@ -68,6 +68,37 @@ module('Unit | Serializer | role', function(hooks) {
         attributes: {
           name: 'Role 1',
           grants: [{value: '*'}, {value: '*'}],
+          principals: []
+        },
+        relationships: {},
+      },
+    });
+  });
+
+  test('it normalizes missing principals to empty array', function (assert) {
+    assert.expect(1);
+    const store = this.owner.lookup('service:store');
+    const serializer = store.serializerFor('role');
+    const role = store.createRecord('role').constructor;
+    const payload = {
+      id: '1',
+      name: 'Role 1',
+      scope: { id: 'o_123' }
+    };
+    const normalized = serializer.normalizeSingleResponse(
+      store,
+      role,
+      payload
+    );
+    assert.deepEqual(normalized, {
+      included: [],
+      data: {
+        id: '1',
+        type: 'role',
+        attributes: {
+          name: 'Role 1',
+          scope: { scope_id: 'o_123' },
+          principals: []
         },
         relationships: {},
       },
diff --git a/addons/api/tests/unit/serializers/target-test.js b/addons/api/tests/unit/serializers/target-test.js
index ab1a07635..94cab05e5 100644
--- a/addons/api/tests/unit/serializers/target-test.js
+++ b/addons/api/tests/unit/serializers/target-test.js
@@ -95,7 +95,7 @@ module('Unit | Serializer | target', function(hooks) {
   });
 
   test('it normalizes missing host_sets to empty array', function (assert) {
-    assert.expect(2);
+    assert.expect(1);
     const store = this.owner.lookup('service:store');
     const serializer = store.serializerFor('target');
     const target = store.createRecord('target').constructor;
@@ -109,7 +109,6 @@ module('Unit | Serializer | target', function(hooks) {
       target,
       payload
     );
-    assert.notOk(payload.bogusArrayField);
     assert.deepEqual(normalized, {
       included: [],
       data: {
diff --git a/ui/core/mirage/serializers/role.js b/ui/core/mirage/serializers/role.js
index 159bdc56c..06009a6f3 100644
--- a/ui/core/mirage/serializers/role.js
+++ b/ui/core/mirage/serializers/role.js
@@ -16,6 +16,7 @@ export default ApplicationSerializer.extend({
       type: 'group'
     }));
     json.principals = [ ...serializedUsers, ...serializedGroups ];
+    if (!json.principals.length) delete json.principals;
     return json;
   }
 });