diff --git a/dGame/dComponents/CollectibleComponent.cpp b/dGame/dComponents/CollectibleComponent.cpp
index fe9d2759a..3d2137e6c 100644
--- a/dGame/dComponents/CollectibleComponent.cpp
+++ b/dGame/dComponents/CollectibleComponent.cpp
@@ -42,8 +42,9 @@ bool CollectibleComponent::CountsFor(const Entity& player) const {
 	}
 }
 
+// LWOCollectibleComponent::Deserialize (0x00c45ec0) reads the id on construction only
 void CollectibleComponent::Serialize(RakNet::BitStream& outBitStream, bool isConstruction) {
-	outBitStream.Write(GetCollectibleId());
+	if (isConstruction) outBitStream.Write(GetCollectibleId());
 }
 
 bool CollectibleComponent::MsgGetObjectReportInfo(GameMessages::GetObjectReportInfo& reportMsg) {
diff --git a/dGame/dUtilities/ReplicaDecoder.cpp b/dGame/dUtilities/ReplicaDecoder.cpp
index 6a2acfde4..6c5f4328a 100644
--- a/dGame/dUtilities/ReplicaDecoder.cpp
+++ b/dGame/dUtilities/ReplicaDecoder.cpp
@@ -389,7 +389,8 @@ namespace {
 				}
 				if (r.Bit()) j["onThreatList"] = r.Bit();
 			} },
-			{ COLLECTIBLE, [](Reader& r, json& j, bool, const auto&) { j["collectibleID"] = r.Get<int16_t>(); } },
+			// LWOCollectibleComponent::Deserialize: the id on construction only
+			{ COLLECTIBLE, [](Reader& r, json& j, bool initial, const auto&) { if (initial) j["collectibleID"] = r.Get<int16_t>(); } },
 			// LWOPetComponent::Deserialize: everything under the dirty bit, the names on updates too
 			{ PET, [](Reader& r, json& j, bool, const auto&) {
 				if (!r.Bit()) return;
diff --git a/tests/dGameTests/dComponentsTests/CollectibleComponentTests.cpp b/tests/dGameTests/dComponentsTests/CollectibleComponentTests.cpp
index 930265c76..74f16c1c8 100644
--- a/tests/dGameTests/dComponentsTests/CollectibleComponentTests.cpp
+++ b/tests/dGameTests/dComponentsTests/CollectibleComponentTests.cpp
@@ -2,6 +2,7 @@
 // the player has that mission.
 #include "GameDependencies.h"
 
+#include "BitStream.h"
 #include "GameMessages.h"
 #include "CDClientDatabase.h"
 #include "CDClientManager.h"
@@ -60,6 +61,24 @@ TEST_F(CollectibleComponentTests, RequirementMissionIsRead) {
 	EXPECT_EQ(other.AddComponent<CollectibleComponent>(999, 5)->GetRequirementMission(), -1); // no row
 }
 
+// LWOCollectibleComponent::Deserialize reads the 16-bit id on construction and nothing on an update. DLU wrote the id
+// on updates too, which the client read as the next components' flag bits.
+TEST_F(CollectibleComponentTests, TheIdIsWrittenOnConstructionOnly) {
+	Entity object(22, info);
+	auto* const collectible = object.AddComponent<CollectibleComponent>(78, 5);
+
+	RakNet::BitStream construction;
+	collectible->Serialize(construction, true);
+	ASSERT_EQ(construction.GetNumberOfBitsUsed(), 16u);
+	int16_t id{};
+	construction.Read(id);
+	EXPECT_EQ(id, 5);
+
+	RakNet::BitStream update;
+	collectible->Serialize(update, false);
+	EXPECT_EQ(update.GetNumberOfBitsUsed(), 0u);
+}
+
 TEST_F(CollectibleComponentTests, AchievementsAndMissingMissionsAlwaysCount) {
 	Entity player(42, info);
 	player.AddComponent<MissionComponent>(-1);