diff --git a/Foundation/NSString.swift b/Foundation/NSString.swift
index 57f651c4f2..b1f7f78162 100644
--- a/Foundation/NSString.swift
+++ b/Foundation/NSString.swift
@@ -27,7 +27,11 @@ func NSLocalizedString(_ key: String,
                        bundle: Bundle = Bundle.main,
                        value: String = "",
                        comment: String) -> String {
-    return bundle.localizedString(forKey: key, value: value, table: tableName)
+    #if os(Android)
+        return key
+    #else
+        return bundle.localizedString(forKey: key, value: value, table: tableName)
+    #endif
 }
 
 #if os(OSX) || os(iOS)
diff --git a/Foundation/URLSession/TaskRegistry.swift b/Foundation/URLSession/TaskRegistry.swift
index b817bcec0a..0e8cb8f676 100644
--- a/Foundation/URLSession/TaskRegistry.swift
+++ b/Foundation/URLSession/TaskRegistry.swift
@@ -72,14 +72,19 @@ extension URLSession._TaskRegistry {
     func remove(_ task: URLSessionTask) {
         let identifier = task.taskIdentifier
         guard identifier != 0 else { fatalError("Invalid task identifier") }
-        guard let tasksIdx = tasks.index(forKey: identifier) else {
-            fatalError("Trying to remove task, but it's not in the registry.")
+        
+        if let tasksIdx = tasks.index(forKey: identifier) {
+            tasks.remove(at: tasksIdx)
+        } else {
+            NSLog("Trying to remove task, but it's not in the registry.")
         }
-        tasks.remove(at: tasksIdx)
-        guard let behaviourIdx = behaviours.index(forKey: identifier) else {
-            fatalError("Trying to remove task's behaviour, but it's not in the registry.")
+        
+        if let behaviourIdx = behaviours.index(forKey: identifier) {
+            behaviours.remove(at: behaviourIdx)
+        } else {
+            NSLog("Trying to remove task's behaviour, but it's not in the registry.")
         }
-        behaviours.remove(at: behaviourIdx)
+        
 
         guard let allTasksFinished = tasksFinishedCallback else { return }
         if self.isEmpty {
@@ -115,4 +120,8 @@ extension URLSession._TaskRegistry {
         }
         return b
     }
+    
+    func containsBehaviour(for task: URLSessionTask) -> Bool {
+        return behaviours[task.taskIdentifier] != nil
+    }
 }
diff --git a/Foundation/URLSession/URLSession.swift b/Foundation/URLSession/URLSession.swift
index 3d503d43c0..f974626043 100644
--- a/Foundation/URLSession/URLSession.swift
+++ b/Foundation/URLSession/URLSession.swift
@@ -546,6 +546,10 @@ internal extension URLSession {
     }
 
     func behaviour(for task: URLSessionTask) -> _TaskBehaviour {
+        guard taskRegistry.containsBehaviour(for: task) else {
+            return .noDelegate
+        }
+        
         switch taskRegistry.behaviour(for: task) {
         case .dataCompletionHandler(let c): return .dataCompletionHandler(c)
         case .downloadCompletionHandler(let c): return .downloadCompletionHandler(c)
diff --git a/Foundation/URLSession/URLSessionTask.swift b/Foundation/URLSession/URLSessionTask.swift
index 82028da0b6..adccfe97cc 100644
--- a/Foundation/URLSession/URLSessionTask.swift
+++ b/Foundation/URLSession/URLSessionTask.swift
@@ -702,24 +702,30 @@ extension _ProtocolClient: URLProtocolClient {
             session.delegateQueue.addOperation {
                 delegate.urlSession(session, task: task, didCompleteWithError: nil)
                 task.state = .completed
-                task.workQueue.async {
+                session.workQueue.async {
                     session.taskRegistry.remove(task)
                 }
             }
         case .noDelegate:
             task.state = .completed
-            session.taskRegistry.remove(task)
+            session.workQueue.async {
+                session.taskRegistry.remove(task)
+            }
         case .dataCompletionHandler(let completion):
             session.delegateQueue.addOperation {
                 completion(`protocol`.properties[URLProtocol._PropertyKey.responseData] as? Data ?? Data(), task.response, nil)
                 task.state = .completed
-                session.taskRegistry.remove(task)
+                session.workQueue.async {
+                    session.taskRegistry.remove(task)
+                }
             }
         case .downloadCompletionHandler(let completion):
             session.delegateQueue.addOperation {
                 completion(`protocol`.properties[URLProtocol._PropertyKey.temporaryFileURL] as? URL, task.response, nil)
                 task.state = .completed
-                session.taskRegistry.remove(task)
+                session.workQueue.async {
+                    session.taskRegistry.remove(task)
+                }
             }
         }
         task._protocol = nil
@@ -786,18 +792,20 @@ extension _ProtocolClient: URLProtocolClient {
             session.delegateQueue.addOperation {
                 delegate.urlSession(session, task: task, didCompleteWithError: error as Error)
                 task.state = .completed
-                task.workQueue.async {
+                session.workQueue.async {
                     session.taskRegistry.remove(task)
                 }
             }
         case .noDelegate:
             task.state = .completed
-            session.taskRegistry.remove(task)
+            session.workQueue.async {
+                session.taskRegistry.remove(task)
+            }
         case .dataCompletionHandler(let completion):
             session.delegateQueue.addOperation {
                 completion(nil, nil, error)
                 task.state = .completed
-                task.workQueue.async {
+                session.workQueue.async {
                     session.taskRegistry.remove(task)
                 }
             }
@@ -805,7 +813,9 @@ extension _ProtocolClient: URLProtocolClient {
             session.delegateQueue.addOperation {
                 completion(nil, nil, error)
                 task.state = .completed
-                session.taskRegistry.remove(task)
+                session.workQueue.async {
+                    session.taskRegistry.remove(task)
+                }
             }
         }
         task._protocol = nil
diff --git a/Foundation/URLSession/http/HTTPURLProtocol.swift b/Foundation/URLSession/http/HTTPURLProtocol.swift
index 8f4dc69bf5..4c218ca400 100644
--- a/Foundation/URLSession/http/HTTPURLProtocol.swift
+++ b/Foundation/URLSession/http/HTTPURLProtocol.swift
@@ -56,7 +56,7 @@ internal class _HTTPURLProtocol: URLProtocol {
             suspend()
         } else {
             self.internalState = .transferFailed
-            guard let error = self.task?.error else { fatalError() }
+            let error = self.task?.error ?? NSError(domain: NSURLErrorDomain, code: URLError.Code.unknown.rawValue)
             completeTask(withError: error)
         }
     }