diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5991c57c4c..c0d09542f7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -82,7 +82,7 @@ message(STATUS "Configuring OpenMW...")
 set(OPENMW_VERSION_MAJOR 0)
 set(OPENMW_VERSION_MINOR 50)
 set(OPENMW_VERSION_RELEASE 0)
-set(OPENMW_LUA_API_REVISION 88)
+set(OPENMW_LUA_API_REVISION 89)
 set(OPENMW_POSTPROCESSING_API_REVISION 3)
 
 set(OPENMW_VERSION_COMMITHASH "")
diff --git a/apps/openmw/mwlua/objectbindings.cpp b/apps/openmw/mwlua/objectbindings.cpp
index 3508fdcd44..0a73acfc42 100644
--- a/apps/openmw/mwlua/objectbindings.cpp
+++ b/apps/openmw/mwlua/objectbindings.cpp
@@ -645,6 +645,9 @@ namespace MWLua
             }
             inventoryT["isResolved"] = [](const InventoryT& inventory) -> bool {
                 const MWWorld::Ptr& ptr = inventory.mObj.ptr();
+                // Avoid initializing custom data
+                if (!ptr.getRefData().getCustomData())
+                    return false;
                 MWWorld::ContainerStore& store = ptr.getClass().getContainerStore(ptr);
                 return store.isResolved();
             };