diff --git a/Analytics/Classes/Integrations/SEGIntegrationsManager.m b/Analytics/Classes/Integrations/SEGIntegrationsManager.m
index 6c663f62a..091569955 100644
--- a/Analytics/Classes/Integrations/SEGIntegrationsManager.m
+++ b/Analytics/Classes/Integrations/SEGIntegrationsManager.m
@@ -372,14 +372,14 @@ - (void)refreshSettings
         if (self.settingsRequest) {
             return;
         }
-        
+
         self.settingsRequest = [self.httpClient settingsForWriteKey:self.configuration.writeKey completionHandler:^(BOOL success, NSDictionary *settings) {
             seg_dispatch_specific_async(_serialQueue, ^{
                 if (success) {
                     [self setCachedSettings:settings];
                 } else {
                     // Hotfix: If settings request fail, fall back to using just Segment integration
-                    // Won't catch situation where this callback never gets called - that will get addressed separately in regular dev 
+                    // Won't catch situation where this callback never gets called - that will get addressed separately in regular dev
                     [self setCachedSettings:@{
                         @"integrations": @{
                             @"Segment.io": @{ @"apiKey": self.configuration.writeKey },
@@ -425,14 +425,9 @@ - (BOOL)isTrackEvent:(NSString *)event enabledForIntegration:(NSString *)key inP
 
 - (void)forwardSelector:(SEL)selector arguments:(NSArray *)arguments options:(NSDictionary *)options
 {
-    // If the event has opted in for syncrhonous delivery, this may be called on any thread.
-    // Only allow one to be delivered at a time.
-    @synchronized(self)
-    {
-        [self.integrations enumerateKeysAndObjectsUsingBlock:^(NSString *key, id<SEGIntegration> integration, BOOL *stop) {
-            [self invokeIntegration:integration key:key selector:selector arguments:arguments options:options];
-        }];
-    }
+    [self.integrations enumerateKeysAndObjectsUsingBlock:^(NSString *key, id<SEGIntegration> integration, BOOL *stop) {
+        [self invokeIntegration:integration key:key selector:selector arguments:arguments options:options];
+    }];
 }
 
 - (void)invokeIntegration:(id<SEGIntegration>)integration key:(NSString *)key selector:(SEL)selector arguments:(NSArray *)arguments options:(NSDictionary *)options
@@ -495,11 +490,10 @@ - (void)flushMessageQueue
 
 - (void)callIntegrationsWithSelector:(SEL)selector arguments:(NSArray *)arguments options:(NSDictionary *)options sync:(BOOL)sync
 {
-    if (sync && self.initialized) {
-        [self forwardSelector:selector arguments:arguments options:options];
-        return;
-    }
-
+    // TODO: Currently we ignore the `sync` argument and queue the event asynchronously.
+    // For integrations that need events to be on the main thread, they'll have to do so
+    // manually and hop back on to the main thread.
+    // Eventually we should figure out a way to handle this in analytics-ios itself.
     seg_dispatch_specific_async(_serialQueue, ^{
         if (self.initialized) {
             [self flushMessageQueue];
diff --git a/AnalyticsTests/AnalyticsTests.swift b/AnalyticsTests/AnalyticsTests.swift
index f43baaafd..554652476 100644
--- a/AnalyticsTests/AnalyticsTests.swift
+++ b/AnalyticsTests/AnalyticsTests.swift
@@ -23,22 +23,22 @@ class AnalyticsTests: QuickSpec {
     var analytics: SEGAnalytics!
     var testMiddleware: TestMiddleware!
     var testApplication: TestApplication!
-    
+
     beforeEach {
       testMiddleware = TestMiddleware()
       config.middlewares = [testMiddleware]
       testApplication = TestApplication()
       config.application = testApplication
       config.trackApplicationLifecycleEvents = true
-      
+
       analytics = SEGAnalytics(configuration: config)
       analytics.test_integrationsManager()?.test_setCachedSettings(settings: cachedSettings)
     }
-    
+
     afterEach {
       analytics.reset()
     }
-    
+
     it("initialized correctly") {
       expect(analytics.configuration.flushAt) == 20
       expect(analytics.configuration.writeKey) == "QUI5ydwIGeFFTa1IvCBUhxL9PyW5B0jE"
@@ -47,30 +47,30 @@ class AnalyticsTests: QuickSpec {
       expect(analytics.configuration.shouldUseBluetooth) == false
       expect(analytics.getAnonymousId()).toNot(beNil())
     }
-    
+
     it("persists anonymousId") {
       let analytics2 = SEGAnalytics(configuration: config)
       expect(analytics.getAnonymousId()) == analytics2.getAnonymousId()
     }
-    
+
     it("persists userId") {
       analytics.identify("testUserId1")
-      
+
       let analytics2 = SEGAnalytics(configuration: config)
       analytics2.test_integrationsManager()?.test_setCachedSettings(settings: cachedSettings)
 
       expect(analytics.test_integrationsManager()?.test_segmentIntegration()?.test_userId()) == "testUserId1"
       expect(analytics2.test_integrationsManager()?.test_segmentIntegration()?.test_userId()) == "testUserId1"
     }
-    
+
     it("continues user activity") {
       let activity = NSUserActivity(activityType: NSUserActivityTypeBrowsingWeb)
       activity.webpageURL = URL(string: "http://www.segment.com")
       analytics.continue(activity)
       let referrer = analytics.test_integrationsManager()?.test_segmentIntegration()?.test_referrer()
-      expect(referrer?["url"] as? String) == "http://www.segment.com"
+      expect(referrer?["url"] as? String).toEventually(equal("http://www.segment.com"))
     }
-    
+
     it("clears user data") {
       analytics.identify("testUserId1", traits: [ "Test trait key" : "Test trait value"])
       analytics.reset()
@@ -90,7 +90,7 @@ class AnalyticsTests: QuickSpec {
       expect(event?.properties?["referring_application"] as? String) == "testApp"
       expect(event?.properties?["url"] as? String) == "test://test"
     }
-    
+
     it("fires Application Opened during UIApplicationWillEnterForeground") {
       testMiddleware.swallowEvent = true
       NotificationCenter.default.post(name: .UIApplicationWillEnterForeground, object: testApplication)
@@ -98,14 +98,14 @@ class AnalyticsTests: QuickSpec {
       expect(event?.event) == "Application Opened"
       expect(event?.properties?["from_background"] as? Bool) == true
     }
-    
+
     it("flushes when UIApplicationDidEnterBackgroundNotification is fired") {
       analytics.track("test")
       NotificationCenter.default.post(name: .UIApplicationDidEnterBackground, object: testApplication)
       expect(testApplication.backgroundTasks.count).toEventually(equal(1))
       expect(testApplication.backgroundTasks[0].isEnded).toEventually(beFalse())
     }
-    
+
     it("protocol conformance should not interfere with UIApplication interface") {
       // In Xcode8/iOS10, UIApplication.h typedefs UIBackgroundTaskIdentifier as NSUInteger,
       // whereas Swift has UIBackgroundTaskIdentifier typealiaed to Int.