[Client] Fix crash when creating Cell from base Cell lacking Pathgrid

apps/openmw/mwmp/RecordHelper.cpp

@@ -373,9 +373,13 @@ void RecordHelper::overrideRecord(const mwmp::CellRecord& record)
         // Note: This has to be done after the new Cell has been created so the Pathgrid override
         //       can correctly determine whether the Cell is an interior or an exterior
         const ESM::Pathgrid* basePathgrid = world->getStore().get<ESM::Pathgrid>().search(record.baseId);
-        ESM::Pathgrid finalPathgrid = *basePathgrid;
-        finalPathgrid.mCell = recordData.mName;
-        world->getModifiableStore().overrideRecord(finalPathgrid);
+
+        if (basePathgrid)
+        {
+            ESM::Pathgrid finalPathgrid = *basePathgrid;
+            finalPathgrid.mCell = recordData.mName;
+            world->getModifiableStore().overrideRecord(finalPathgrid);
+        }
     }
     else
     {