diff --git a/.github/workflows/mac_arm64.yml b/.github/workflows/mac_arm64.yml
index c5a8fecd63..38dcbcf946 100644
--- a/.github/workflows/mac_arm64.yml
+++ b/.github/workflows/mac_arm64.yml
@@ -33,6 +33,7 @@ jobs:
     if: ${{ needs.call-check-pr-status.outputs.should_continue == 'true' }}
     runs-on: macos-latest
     strategy:
+      fail-fast: false
       matrix:
         build_type: [debug, release]
     steps:
diff --git a/core/src/ten_runtime/binding/python/interface/ten_runtime/global_thread_manager.py b/core/src/ten_runtime/binding/python/interface/ten_runtime/global_thread_manager.py
index 1e68ed874c..a46b30b21a 100644
--- a/core/src/ten_runtime/binding/python/interface/ten_runtime/global_thread_manager.py
+++ b/core/src/ten_runtime/binding/python/interface/ten_runtime/global_thread_manager.py
@@ -18,25 +18,26 @@ class GlobalThreadManager:
     _instance: "GlobalThreadManager | None" = None
     _lock: threading.Lock = threading.Lock()
 
+    _ref_count: int
+    _main_thread: threading.Thread | None
+    _main_loop: asyncio.AbstractEventLoop | None
+    _stop_event: asyncio.Event
+    _loop_ready_event: threading.Event
+
     def __new__(cls):
         if cls._instance is None:
             with cls._lock:
                 if cls._instance is None:
-                    cls._instance = super().__new__(cls)
-                    cls._instance._initialized = False
+                    instance = super().__new__(cls)
+                    instance._ref_count = 0
+                    instance._main_thread = None
+                    instance._main_loop = None
+                    instance._stop_event = asyncio.Event()
+                    instance._loop_ready_event = threading.Event()
+                    # Publish only after initialization, while holding the lock.
+                    cls._instance = instance
         return cls._instance
 
-    def __init__(self):
-        if self._initialized:
-            return
-
-        self._ref_count: int = 0
-        self._main_thread: threading.Thread | None = None
-        self._main_loop: asyncio.AbstractEventLoop | None = None
-        self._stop_event: asyncio.Event = asyncio.Event()
-        self._loop_ready_event: threading.Event = threading.Event()
-        self._initialized: bool = True
-
     def reset(self):
         with self._lock:
             self._ref_count = 0
@@ -44,7 +45,6 @@ def reset(self):
             self._main_loop = None
             self._stop_event = asyncio.Event()
             self._loop_ready_event = threading.Event()
-            self._initialized = True
 
     def get_or_start_thread(
         self, ten_env: "TenEnv"