diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0065b77..bf0ab9a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # CHANGELOG
 
+## [3.8.4] - 2026-06-24
+
+- [Fixed] `_ping_pong` send now classifies `ConnectionResetError` / `BrokenPipeError` / `ConnectionAbortedError` / `WebSocketConnectionClosedException` (the `TRANSIENT_WS_ERRORS`) at WARNING instead of ERROR+traceback. The background thread no longer emits noisy ERROR logs with full stacktraces on peer resets (the root cause of the reported "unhandled ConnectionResetError" during `_ping_pong`). Reconnect via `wss_conn_halted` is unchanged; only log level and noise. (OPS-3616)
+- [Changed] Added deterministic regression tests for transient vs. fatal send errors inside `_ping_pong` (modeled exactly on the OPS-3485 recv tests; <100 ms, no sockets, no sleeps). (OPS-3616)
+
 ## [3.8.3] - 2026-06-24
 
 - [Fixed] `query`, `mutate`, `async_query`, and `async_mutate` no longer collapse a raised transport exception into `[{"message": ""}]`. httpx timeout and connection-reset exceptions carry an empty message (`str(httpx.ReadTimeout(""))` is `""`), so the previous `errors = [{"message": str(e)}]` surfaced a blank, undiagnosable error — most visibly on `async_mutate`, where async httpx timeouts always stringify to "". A new `exception_errors` helper falls back to `repr(error)` when the message is blank, preserving the exception class name (e.g. `ReadTimeout('')`) so the caller can tell what actually failed. Added an integration test that drives a real `GraphQLClient` against a local HTTP server stalled past `post_timeout`.
@@ -14,6 +19,7 @@
 - [Fixed] `async_cleanup` now actually closes a live async client. Its previous usability probe called `httpx.AsyncClient.get_timeout()`, a method that doesn't exist, so every client went down the "let GC handle it" branch and leaked. (Same broken probe in `_get_async_client` meant the cached client was recreated on every call; recreation now closes the old client first, so nothing leaks.)
 - [Changed] Removed the unused `_close_async_client` private method, superseded by `_drop_async_client`.
 
+
 ## [3.8.0] - 2026-05-28
 
 - [Fixed] `addEnvironment` no longer wipes an existing environment's `wss`/`url`/`headers`/`post_timeout`/`ipv4_only` when re-registering the same environment name without those arguments. Re-registration now MERGES — omitted arguments keep their previous values. Previously a second `addEnvironment("prod", url=..., headers=...)` on the shared (Singleton) client — e.g. a library configuring its own environment — silently reset `wss` to `None`, which crashed the WSS reconnect loop in `_new_conn` with `TypeError: argument of type 'NoneType' is not a container` and produced endless "Failed connecting to None" errors. This was the root cause of the production incident. (OPS-3496)
diff --git a/pygqlc/GraphQLClient.py b/pygqlc/GraphQLClient.py
index 801af56..4ea2e5c 100644
--- a/pygqlc/GraphQLClient.py
+++ b/pygqlc/GraphQLClient.py
@@ -812,10 +812,16 @@ def _ping_pong(self):
                     # No need to log normal ping operations
                 except Exception as e:
                     if not self.closing:
-                        log(
-                            LogLevel.ERROR,
-                            "error trying to send ping, WSS Pipe is broken",
-                        )
+                        if isinstance(e, TRANSIENT_WS_ERRORS):
+                            log(
+                                LogLevel.WARNING,
+                                "WSS connection reset or closed by peer",
+                            )
+                        else:
+                            log(
+                                LogLevel.ERROR,
+                                "error trying to send ping, WSS Pipe is broken",
+                            )
                         self.wss_conn_halted = True
 
     def _registerSub(self, _id=None):
diff --git a/pygqlc/__version__.py b/pygqlc/__version__.py
index 429dcfe..9fd9cda 100644
--- a/pygqlc/__version__.py
+++ b/pygqlc/__version__.py
@@ -1 +1 @@
-__version__ = "3.8.3"
+__version__ = "3.8.4"
diff --git a/tests/pygqlc/gql_client/test_subscribe.py b/tests/pygqlc/gql_client/test_subscribe.py
index 2697592..638b22e 100644
--- a/tests/pygqlc/gql_client/test_subscribe.py
+++ b/tests/pygqlc/gql_client/test_subscribe.py
@@ -145,6 +145,14 @@ def _stop():
     return _stop
 
 
+def _run_ping_pong(gql, timeout=1.0):
+    """Run _ping_pong in a daemon thread; fail (not hang) if it doesn't exit."""
+    thread = threading.Thread(target=gql._ping_pong, daemon=True)
+    thread.start()
+    thread.join(timeout)
+    assert not thread.is_alive(), "ping pong loop did not terminate"
+
+
 @pytest.fixture
 def routing_client():
     """A fresh GraphQLClient (bypassing the process-wide singleton cache) wired to a mock
@@ -248,6 +256,77 @@ def _recv_then_close():
     assert not any("invalid WSS message" in msg for level, msg in records)
 
 
+def test_ping_pong_connection_reset_logged_as_warning(routing_client):
+    """OPS-3616: ConnectionResetError from send in _ping_pong is transient — log at
+    WARNING (not ERROR+traceback) and set wss_conn_halted to trigger reconnection.
+    The send error must be classified like recv transient errors (OPS-3485)."""
+    gql = routing_client
+    gql.pingIntervalTime = 0
+    gql.pingTimer = 0
+
+    send_called = [0]
+
+    def send_effect(data):
+        send_called[0] += 1
+        if send_called[0] == 1:
+            raise ConnectionResetError(104, "Connection reset by peer")
+        return None
+
+    gql._conn.send.side_effect = send_effect
+
+    sleep_calls = [0]
+
+    def sleepy(*args):
+        sleep_calls[0] += 1
+        if sleep_calls[0] > 2:
+            gql.closing = True
+        return None
+
+    with patch("time.sleep", side_effect=sleepy), _capture_logs() as records:
+        _run_ping_pong(gql)
+
+    assert gql.wss_conn_halted is True
+    assert send_called[0] == 1
+    assert any(
+        level == LogLevel.WARNING and "reset or closed by peer" in msg
+        for level, msg in records
+    )
+    assert not any(
+        level == LogLevel.ERROR and "error trying to send ping" in msg
+        for level, msg in records
+    )
+
+
+def test_ping_pong_unexpected_error_logged_as_error(routing_client):
+    """A non-transient error from _ping_pong send must still surface at ERROR
+    level (and halt)."""
+    gql = routing_client
+    gql.pingIntervalTime = 0
+    gql.pingTimer = 0
+
+    def send_effect(data):
+        raise ValueError("unexpected ping send failure")
+
+    gql._conn.send.side_effect = send_effect
+
+    sleep_calls = [0]
+
+    def sleepy(*args):
+        sleep_calls[0] += 1
+        if sleep_calls[0] > 2:
+            gql.closing = True
+        return None
+
+    with patch("time.sleep", side_effect=sleepy), _capture_logs() as records:
+        _run_ping_pong(gql)
+
+    assert gql.wss_conn_halted is True
+    assert any(
+        level == LogLevel.ERROR and "error trying to send ping" in msg
+        for level, msg in records
+    )
+
+
 def test_addenvironment_reregister_preserves_wss():
     """OPS-3496: re-registering an existing environment without `wss` (as a library
     configuring the shared Singleton client does) must NOT wipe the previously-set