diff --git a/packages/datastore/__tests__/outbox.test.ts b/packages/datastore/__tests__/outbox.test.ts
index c74f1866d2e..06f21f7f1f5 100644
--- a/packages/datastore/__tests__/outbox.test.ts
+++ b/packages/datastore/__tests__/outbox.test.ts
@@ -33,7 +33,7 @@ describe('Outbox tests', () => {
 	beforeAll(async () => {
 		jest.resetAllMocks();
 
-		await initializeOutbox();
+		await instantiateOutbox();
 
 		const newModel = new Model({
 			field1: 'Some value',
@@ -207,13 +207,13 @@ describe('Outbox tests', () => {
 
 		await Storage.runExclusive(async s => {
 			// process mutation response, which dequeues updatedModel1
-			// and syncs its version to the remaining item in the mutation queue
+			// but SHOULD NOT sync the _version, since the data in the response is different
 			await processMutationResponse(s, response);
 
 			const inProgress = await outbox.peek(s);
 			const inProgressData = JSON.parse(inProgress.data);
-			// updatedModel3 should now be in progress with the _version from the mutation response
 
+			// updatedModel2 should now be in progress with the _version from the mutation response
 			expect(inProgressData.field1).toEqual('another value2');
 
 			const oldVersion = (modelData as any)._version;
@@ -231,7 +231,7 @@ describe('Outbox tests', () => {
 
 // performs all the required dependency injection
 // in order to have a functional Outbox without the Sync Engine
-async function initializeOutbox(): Promise<void> {
+async function instantiateOutbox(): Promise<void> {
 	({ initSchema, DataStore } = require('../src/datastore/datastore'));
 	const classes = initSchema(testSchema());
 	const ownSymbol = Symbol('sync');
diff --git a/packages/datastore/src/util.ts b/packages/datastore/src/util.ts
index 38bf7f270e4..ca987bcb51d 100644
--- a/packages/datastore/src/util.ts
+++ b/packages/datastore/src/util.ts
@@ -468,7 +468,10 @@ export function objectsEqual(objA: object, objB: object): boolean {
 	let a = objA;
 	let b = objB;
 
-	if (Array.isArray(a) && !Array.isArray(b)) {
+	if (
+		(Array.isArray(a) && !Array.isArray(b)) ||
+		(Array.isArray(b) && !Array.isArray(a))
+	) {
 		return false;
 	}
 
diff --git a/scripts/build.js b/scripts/build.js
index 61b9097aea7..8b133b08cf6 100644
--- a/scripts/build.js
+++ b/scripts/build.js
@@ -157,7 +157,13 @@ async function buildES5(typeScriptCompiler) {
 	let compilerOptions = {
 		esModuleInterop: true,
 		noImplicitAny: false,
-		lib: ['dom', 'es2017', 'esnext.asynciterable', 'es2018.asyncgenerator'],
+		lib: [
+			'dom',
+			'es2017',
+			'esnext.asynciterable',
+			'es2018.asyncgenerator',
+			'es2019.object',
+		],
 		downlevelIteration: true,
 		jsx: jsx,
 		sourceMap: true,
@@ -202,7 +208,13 @@ function buildES6(typeScriptCompiler) {
 	let compilerOptions = {
 		esModuleInterop: true,
 		noImplicitAny: false,
-		lib: ['dom', 'es2017', 'esnext.asynciterable', 'es2018.asyncgenerator'],
+		lib: [
+			'dom',
+			'es2017',
+			'esnext.asynciterable',
+			'es2018.asyncgenerator',
+			'es2019.object',
+		],
 		downlevelIteration: true,
 		jsx: jsx,
 		sourceMap: true,