diff --git a/Source/lua/modules/monsters.cpp b/Source/lua/modules/monsters.cpp
index 35e796afb..3fbb01b36 100644
--- a/Source/lua/modules/monsters.cpp
+++ b/Source/lua/modules/monsters.cpp
@@ -18,7 +18,7 @@ namespace {
 void AddMonsterDataFromTsv(const std::string_view path)
 {
 	DataFile dataFile = DataFile::loadOrDie(path);
-	LoadMonstDatFromFile(dataFile, path);
+	LoadMonstDatFromFile(dataFile, path, true);
 }
 
 void AddUniqueMonsterDataFromTsv(const std::string_view path)
diff --git a/Source/monstdat.cpp b/Source/monstdat.cpp
index 78e2876ed..c8487bb09 100644
--- a/Source/monstdat.cpp
+++ b/Source/monstdat.cpp
@@ -322,11 +322,13 @@ tl::expected<UniqueMonsterPack, std::string> ParseUniqueMonsterPack(std::string_
 
 } // namespace
 
-void LoadMonstDatFromFile(DataFile &dataFile, const std::string_view filename)
+void LoadMonstDatFromFile(DataFile &dataFile, const std::string_view filename, bool grow)
 {
 	dataFile.skipHeaderOrDie(filename);
 
-	MonstersData.reserve(MonstersData.size() + dataFile.numRecords());
+	if (grow) {
+		MonstersData.reserve(MonstersData.size() + dataFile.numRecords());
+	}
 
 	for (DataFileRecord record : dataFile) {
 		if (MonstersData.size() >= static_cast<size_t>(NUM_MAX_MTYPES)) {
@@ -396,7 +398,6 @@ void LoadMonstDatFromFile(DataFile &dataFile, const std::string_view filename)
 
 		reader.readInt("exp", monster.exp);
 	}
-	MonstersData.shrink_to_fit();
 }
 
 namespace {
@@ -408,9 +409,11 @@ void LoadMonstDat()
 	MonstersData.clear();
 	AdditionalMonsterIdStringsToIndices.clear();
 	MonstersData.resize(NUM_DEFAULT_MTYPES); // ensure the hardcoded monster type slots are filled
-	LoadMonstDatFromFile(dataFile, filename);
+	LoadMonstDatFromFile(dataFile, filename, false);
 
 	LuaEvent("MonsterDataLoaded");
+
+	MonstersData.shrink_to_fit();
 }
 
 } // namespace
@@ -451,8 +454,6 @@ void LoadUniqueMonstDatFromFile(DataFile &dataFile, std::string_view filename)
 			return tl::make_unexpected("Invalid value. NOTE: Parser is incomplete");
 		});
 	}
-
-	UniqueMonstersData.shrink_to_fit();
 }
 
 namespace {
@@ -466,6 +467,8 @@ void LoadUniqueMonstDat()
 	LoadUniqueMonstDatFromFile(dataFile, filename);
 
 	LuaEvent("UniqueMonsterDataLoaded");
+
+	UniqueMonstersData.shrink_to_fit();
 }
 
 } // namespace
diff --git a/Source/monstdat.h b/Source/monstdat.h
index 3d3afd5ba..9c1730eb3 100644
--- a/Source/monstdat.h
+++ b/Source/monstdat.h
@@ -337,7 +337,7 @@ extern std::vector<MonsterData> MonstersData;
 extern const _monster_id MonstConvTbl[];
 extern std::vector<UniqueMonsterData> UniqueMonstersData;
 
-void LoadMonstDatFromFile(DataFile &dataFile, std::string_view filename);
+void LoadMonstDatFromFile(DataFile &dataFile, std::string_view filename, bool grow);
 void LoadUniqueMonstDatFromFile(DataFile &dataFile, std::string_view filename);
 void LoadMonsterData();