diff --git a/include/phasar/ControlFlow/CallGraph.h b/include/phasar/ControlFlow/CallGraph.h
index 7751aa963..d73a1b578 100644
--- a/include/phasar/ControlFlow/CallGraph.h
+++ b/include/phasar/ControlFlow/CallGraph.h
@@ -296,7 +296,7 @@ CallGraph<N, F>::deserialize(const CallGraphData &PrecomputedCG,
       const auto &CS = std::invoke(GetInstructionFromId, JId);
       if (!CS) {
         PHASAR_LOG_LEVEL_CAT(WARNING, "CallGraph",
-                             "Invalid CAll-Instruction Id: " << JId);
+                             "Invalid Call-Instruction Id: " << JId);
       }
 
       CGBuilder.addCallEdge(CS, Fun);
diff --git a/include/phasar/ControlFlow/CallGraphData.h b/include/phasar/ControlFlow/CallGraphData.h
index 4321d7cea..ed50d66e4 100644
--- a/include/phasar/ControlFlow/CallGraphData.h
+++ b/include/phasar/ControlFlow/CallGraphData.h
@@ -19,7 +19,8 @@
 
 namespace psr {
 struct CallGraphData {
-  std::unordered_map<std::string, std::vector<int>> FToFunctionVertexTy{};
+  // Mangled FunName --> [CS-IDs]
+  std::unordered_map<std::string, std::vector<uint32_t>> FToFunctionVertexTy{};
 
   CallGraphData() noexcept = default;
   void printAsJson(llvm::raw_ostream &OS);
diff --git a/lib/ControlFlow/CallGraphData.cpp b/lib/ControlFlow/CallGraphData.cpp
index 8b0f13a85..5b4e254f6 100644
--- a/lib/ControlFlow/CallGraphData.cpp
+++ b/lib/ControlFlow/CallGraphData.cpp
@@ -10,6 +10,7 @@
 #include "phasar/ControlFlow/CallGraphData.h"
 
 #include "phasar/Utils/IO.h"
+#include "phasar/Utils/Logger.h"
 #include "phasar/Utils/NlohmannLogging.h"
 
 namespace psr {
@@ -20,10 +21,11 @@ static CallGraphData getDataFromJson(const nlohmann::json &Json) {
   for (const auto &[FVal, FunctionVertexTyVals] :
        Json.get<nlohmann::json::object_t>()) {
     auto &FValMappedVector = ToReturn.FToFunctionVertexTy[FVal];
-    FValMappedVector.reserve(FunctionVertexTyVals.size());
-
-    for (const auto &Curr : FunctionVertexTyVals) {
-      FValMappedVector.push_back(Curr.get<int>());
+    if (FunctionVertexTyVals.is_array()) {
+      FValMappedVector = FunctionVertexTyVals.get<std::vector<uint32_t>>();
+    } else if (!FunctionVertexTyVals.is_null()) {
+      PHASAR_LOG_LEVEL(
+          WARNING, "Invalid Function-CS IDs Array: " << FunctionVertexTyVals);
     }
   }
 
diff --git a/lib/PhasarLLVM/TypeHierarchy/DIBasedTypeHierarchy.cpp b/lib/PhasarLLVM/TypeHierarchy/DIBasedTypeHierarchy.cpp
index ce8f8ab27..be0f02c07 100644
--- a/lib/PhasarLLVM/TypeHierarchy/DIBasedTypeHierarchy.cpp
+++ b/lib/PhasarLLVM/TypeHierarchy/DIBasedTypeHierarchy.cpp
@@ -254,9 +254,6 @@ static const llvm::DIType *stringToDIType(const llvm::DebugInfoFinder &DIF,
   llvm::report_fatal_error("DIType doesn't exist " + DITypeName);
 }
 
-// NOLINTNEXTLINE
-static constexpr char NullFunName[] = "__null__";
-
 DIBasedTypeHierarchy::DIBasedTypeHierarchy(
     const LLVMProjectIRDB *IRDB, const DIBasedTypeHierarchyData &SerializedData)
     : TransitiveDerivedIndex(SerializedData.TransitiveDerivedIndex) {
@@ -287,7 +284,7 @@ DIBasedTypeHierarchy::DIBasedTypeHierarchy(
 
     CurrVTable.reserve(Curr.size());
     for (const auto &FuncName : Curr) {
-      if (FuncName == NullFunName) {
+      if (FuncName == LLVMVFTable::NullFunName) {
         CurrVTable.push_back(nullptr);
       }
       CurrVTable.push_back(IRDB->getFunction(FuncName));
@@ -375,7 +372,7 @@ DIBasedTypeHierarchyData DIBasedTypeHierarchy::getTypeHierarchyData() const {
         CurrVTableAsString.push_back(Func->getName().str());
         continue;
       }
-      CurrVTableAsString.emplace_back(NullFunName);
+      CurrVTableAsString.emplace_back(LLVMVFTable::NullFunName);
     }
 
     Data.VTables.push_back(std::move(CurrVTableAsString));