diff --git a/colobot-base/level/robotmain.cpp b/colobot-base/level/robotmain.cpp
index 92270cb6..61072531 100644
--- a/colobot-base/level/robotmain.cpp
+++ b/colobot-base/level/robotmain.cpp
@@ -4654,6 +4654,7 @@ bool CRobotMain::IOIsBusy()
 //! Writes an object into the backup file
 void CRobotMain::IOWriteObject(CLevelParserLine* line, CObject* obj, const std::string& programDir, int objRank, bool directProgramStorageIndex)
 {
+    assert(obj->GetType() != OBJECT_NULL);
     line->AddParam("type", std::make_unique<CLevelParserParam>(obj->GetType()));
     line->AddParam("id", std::make_unique<CLevelParserParam>(obj->GetID()));
     line->AddParam("pos", std::make_unique<CLevelParserParam>(obj->GetPosition()/g_unit));
diff --git a/colobot-base/object/old_object.cpp b/colobot-base/object/old_object.cpp
index f3b2485a..68f3af12 100644
--- a/colobot-base/object/old_object.cpp
+++ b/colobot-base/object/old_object.cpp
@@ -286,8 +286,8 @@ void COldObject::DeleteObject(bool bAll)
             if (m_power->Implements(ObjectInterfaceType::Old))
             {
                 dynamic_cast<COldObject&>(*m_power).SetTransporter(nullptr);
-                dynamic_cast<COldObject&>(*m_power).DeleteObject(bAll);
             }
+            CObjectManager::GetInstance().DeleteObject(m_power);
             m_power = nullptr;
         }
         if (m_cargo != nullptr)
@@ -295,8 +295,8 @@ void COldObject::DeleteObject(bool bAll)
             if (m_cargo->Implements(ObjectInterfaceType::Old))
             {
                 dynamic_cast<COldObject&>(*m_cargo).SetTransporter(nullptr);
-                dynamic_cast<COldObject&>(*m_cargo).DeleteObject(bAll);
             }
+            CObjectManager::GetInstance().DeleteObject(m_cargo);
             m_cargo = nullptr;
         }
     }