So, in legendary maps (and even in heroic, but really rare), there are places where boxes etc. just get deleted if placed there (e.g. sniper spot on blackout. a box up there is impossible.) The reason why it gets deleted is because it touches the invisible death wall of the map. But sometimes (like in foundry) It even gets deleted at a place near the wall behind the crane. There is no death border. Someone knows how to get objects there? (By the way: Not spartan-spawning. It is much too hard to get them to the right place like that)
I know what you're describing. To save objects within a death boundry or places where it just automatically gets deleted, hold the item in the place you want, whilst still holding the item, press start and save changes. Whilst still paused, end the game and reload the map again. The item will be there. Just be careful though, if you use this method to get an item far away from the map, you will not be able to edit it or delete it. Hope that helps you.
I think I have just been standing on the Schlauch lol. I tried to solve this problem much more difficult than it was in fact... And Zombiesteve: A know that I have to press start to save changes. ...