diff --git a/livekit-rtc/livekit/rtc/_ffi_client.py b/livekit-rtc/livekit/rtc/_ffi_client.py
index 3ae44aac..aab703f6 100644
--- a/livekit-rtc/livekit/rtc/_ffi_client.py
+++ b/livekit-rtc/livekit/rtc/_ffi_client.py
@@ -288,7 +288,7 @@ def request(self, req: proto_ffi.FfiRequest) -> proto_ffi.FfiResponse:
             )
         proto_data = req.SerializeToString()
         proto_len = len(proto_data)
-        data = (ctypes.c_ubyte * proto_len)(*proto_data)
+        data = ctypes.cast(ctypes.c_char_p(proto_data), ctypes.POINTER(ctypes.c_ubyte))
 
         resp_ptr = ctypes.POINTER(ctypes.c_ubyte)()
         resp_len = ctypes.c_size_t()
diff --git a/livekit-rtc/tests/test_ffi_client.py b/livekit-rtc/tests/test_ffi_client.py
new file mode 100644
index 00000000..53873884
--- /dev/null
+++ b/livekit-rtc/tests/test_ffi_client.py
@@ -0,0 +1,44 @@
+# Copyright 2026 LiveKit, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""FfiClient.request tests against the native library."""
+
+import subprocess
+import sys
+
+# Runs in a fresh interpreter: ctypes reuses a `c_ubyte * n` type that another
+# live object still holds, which would hide a new one made per request.
+_COUNT_ARRAY_TYPES_IN_GARBAGE = """
+import ctypes
+import gc
+
+from livekit import rtc
+
+gc.collect()
+gc.set_debug(gc.DEBUG_SAVEALL)
+for _ in range(50):
+    rtc.AudioProcessingModule()
+gc.collect()
+print(sum(isinstance(o, type(ctypes.Array)) for o in gc.garbage))
+"""
+
+
+def test_request_leaves_no_ctypes_array_type_in_garbage() -> None:
+    result = subprocess.run(
+        [sys.executable, "-c", _COUNT_ARRAY_TYPES_IN_GARBAGE],
+        capture_output=True,
+        text=True,
+        check=True,
+    )
+    assert result.stdout.strip() == "0"