diff --git a/circuitmatter/session.py b/circuitmatter/session.py
index eb5a657..247f3fc 100644
--- a/circuitmatter/session.py
+++ b/circuitmatter/session.py
@@ -140,7 +140,8 @@ def decode(self, buffer):
         )
         self.general_code = GeneralCode(self.general_code)
         self.protocol_data = buffer[8:]
-        self.protocol_id = protocol.ProtocolId(self.protocol_id)
+        if self.protocol_id in protocol.ProtocolId:
+            self.protocol_id = protocol.ProtocolId(self.protocol_id)
 
         if self.protocol_id == protocol.ProtocolId.SECURE_CHANNEL:
             self.protocol_code = SecureChannelProtocolCode(self.protocol_code)
diff --git a/tests/test_message_reception_state.py b/tests/test_message_reception_state.py
index 43fa254..71b191e 100644
--- a/tests/test_message_reception_state.py
+++ b/tests/test_message_reception_state.py
@@ -1,4 +1,4 @@
-from circuitmatter import MessageReceptionState
+from circuitmatter.session import MessageReceptionState
 
 
 def test_basics():
diff --git a/tests/test_status_report.py b/tests/test_status_report.py
index 24ab7e9..32f6180 100644
--- a/tests/test_status_report.py
+++ b/tests/test_status_report.py
@@ -1,4 +1,5 @@
-from circuitmatter import StatusReport, GeneralCode, ProtocolId
+from circuitmatter.session import StatusReport, GeneralCode
+from circuitmatter.protocol import ProtocolId
 
 
 def test_example1():
diff --git a/tests/test_tlv.py b/tests/test_tlv.py
index 3b4a8c2..74132d5 100644
--- a/tests/test_tlv.py
+++ b/tests/test_tlv.py
@@ -111,7 +111,7 @@ def test_signed_int_negative_17_encode(self):
     def test_signed_int_42_two_octet_encode(self):
         s = SignedIntTwoOctet()
         s.i = 42
-        assert s.encode().tobytes() == b"\x15\x21\x00\x2a\x00\x18"
+        assert s.encode().tobytes() == b"\x15\x20\x00\x2a\x18"
 
     def test_signed_int_negative_170000_encode(self):
         s = SignedIntFourOctet()
@@ -547,10 +547,7 @@ def test_inner_struct_encode(self):
         inner.a = 42
         inner.b = -17
         s.s = inner
-        assert (
-            s.encode().tobytes()
-            == b"\x15\x35\x00\x22\x00\x2a\x00\x00\x00\x22\x01\xef\xff\xff\xff\x18\x18"
-        )
+        assert s.encode().tobytes() == b"\x15\x35\x00\x20\x00\x2a\x20\x01\xef\x18\x18"
 
     def test_inner_struct_encode_empty(self):
         s = OuterStruct()
@@ -581,7 +578,7 @@ def test_encode(self):
         s.b = -17
         assert (
             s.encode().tobytes()
-            == b"\x15\xc2\xda\x0a\x00\x0f\x23\x01\x2a\x00\x00\x00\xe2\xda\x0a\x00\x0f\x45\x23\x01\x00\xef\xff\xff\xff\x18"
+            == b"\x15\xc0\xda\x0a\x00\x0f\x23\x01\x2a\xe0\xda\x0a\x00\x0f\x45\x23\x01\x00\xef\x18"
         )
 
 
@@ -601,10 +598,7 @@ def test_encode(self):
         inner.a = 42
         inner.b = -17
         s.sublist = inner
-        assert (
-            s.encode().tobytes()
-            == b"\x15\x37\x00\x22\x00\x2a\x00\x00\x00\x22\x01\xef\xff\xff\xff\x18\x18"
-        )
+        assert s.encode().tobytes() == b"\x15\x37\x00\x20\x00\x2a\x20\x01\xef\x18\x18"
 
 
 class OuterStructArray(tlv.Structure):
@@ -620,7 +614,7 @@ def test_encode(self):
         s.a = [inner]
         assert (
             s.encode().tobytes()
-            == b"\x15\x36\x00\x17\x22\x00\x2a\x00\x00\x00\x22\x01\xef\xff\xff\xff\x18\x18\x18"
+            == b"\x15\x36\x00\x17\x20\x00\x2a\x20\x01\xef\x18\x18\x18"
         )
 
     def test_encode2(self):
@@ -631,5 +625,5 @@ def test_encode2(self):
         s.a = [inner, inner]
         assert (
             s.encode().tobytes()
-            == b"\x15\x36\x00\x17\x22\x00\x2a\x00\x00\x00\x22\x01\xef\xff\xff\xff\x18\x17\x22\x00\x2a\x00\x00\x00\x22\x01\xef\xff\xff\xff\x18\x18\x18"
+            == b"\x15\x36\x00\x17\x20\x00\x2a\x20\x01\xef\x18\x17\x20\x00\x2a\x20\x01\xef\x18\x18\x18"
         )