So I have created this tower mostly metal and 5 levels with some objects (glass door, bulkhead lamp (oval and single), and a square manhole cover).
I have also within this blueprint used a blueprint of a metal staircase added into each level of the building and a metal beam consisting of one-block segments of a beam. Nothing fancy.
The whole contraption blueprints fine and places fine, but the above mentioned objects "falls off" at random - sometimes a few, sometimes all and end up as a wooden box containing the object wherever gravity lands them.
Also, at random, some of the staircase steps are visible but you'll fall through and the step(s) cannot be removed with the sledgehammer - it's like it's not there. Ctrl-F4-F7 mass delete works.
This is single player, btw, I have tried different worlds (SP) and same thing happens at random.
In my main world game same thing happens but I also have an area where I cannot delete vegetations, blocks and even pick an apple - that crashes the game without any error message except the Windows msg stating the game has stopped responding. Found nothing in the logfiles.
I have the following plugins (ToolsAPI as 0ToolsAPI, AutoDoors, BlueLib-0.2.0 and ModelLoader) - I am using the AutoDoors in my main game and seems to work ok except for the delete-stuff-crash and random Drop-O-Things from my Tower BP.
Any ideas for me to troubleshoot? I'm not that traversed (yet) in Unity. Oh, Steam game files verify is ok. 
