When an object tries to load while having “ignore fog of war” turned on, it will fail to load if the fog of war was placed before the the object. Another user had similar issues and a fix per save here: https://steamcommunity.com/app/286160/discussions/3/2440335959622251096/
Ran into this problem recently, i hope it gets fixed.
Having the same problem right now, just to add to this, I saved my custom objects in a box/bag and it doesn’t trigger the issue when they are in. The issue only exists when the custom object is loaded in the table
Oh my god, thank you for picking this up!