To reproduce(though I doubt anyone needs to test it) you can use this lua command in lag mode: ```world.createObject(selected.recordId):teleport(selected.cell,selected.position);selected:remove()``` After placing the door, aggro an NPC on the other side, and return to the opposite side via tcl or some other means. The NPC will walk into the door forever. This is most likely caused by [this function](https://gitlab.com/OpenMW/openmw/-/blob/master/apps/openmw/mwworld/cellstore.hpp#L302), which has a note about a const version of foreach being needed. It's used(in this context) [here](https://gitlab.com/OpenMW/openmw/-/blob/master/apps/openmw/mwmechanics/obstacle.cpp#L57).