You should check how the event command work, it implies to change some of the map properties to avoid bugs/side effects. It's in EventCommand/CreateObjectInMap.js:

            let id = ++Scene.Map.current.maxObjectsID;

            let position = Position.createFromVector3(currentState.position);

            let globalPortion = position.getGlobalPortion();

            Scene.Map.current.allObjects[id] = position;

            let newObject = new MapObject(System.MapObject.createFromModelID(this.modelID.getValue(), id), currentState.position);

            if (this.isStockID) {

                Game.current.variables[this.stockID.getValue(true)] = id;

            }

            Game.current.getPortionDatas(Scene.Map.current.id, globalPortion).m.push(newObject);

            Game.current.getPortionDatas(Scene.Map.current.id, globalPortion).min.push(newObject);

            newObject.changeState();