It's probably been brought up already, but I've been playing since release and I've noticed that certain objects that I hand place around my settlement randomly disappear.

Sometimes they haven't actually "disappeared" but rather clipped through whatever object I placed them on and end up on the ground. This can be equally annoying because I then have to deconstruct/move around parts of my settlement just to retrieve said object.

In other cases objects have simply vanished into thin air, never to be seen again. It wouldn't be such a big deal if it weren't for the fact that hand placing items can be a tedious and frustrating process. It's very annoying to come back to your base only to find out that the item you spent 10 minutes positioning to get the look you want has mysteriously vanished into oblivion.

I figured it would be the case. Fallout 3 would have the same problem but it was somewhat rare. I haven't placed any hard to find items out in fallout 4 yet just in case the game is still a little buggy and I come back and my collection of items has disappeared!

My mate quit decorating after we noticed beer bottles, Nuka cola's, quantums, cherries, + fans, coolant and lunchboxes and dog bowls,

All fall through tables, desks, bars, and floors.
Eventually.

Do not store anything in the open until they fix this buggy game. Wish you the best.
Do not leave fusion cores in armor also, if a raider attack happens and a trader gets in a suit, it disappears and their body changes shape, making them glitch and unable to exit armor.
If it does happen, stealth, or hide and pickpocket the fusion core (normally 7% chance to steal), but quicksave before and try 10-20 times. It works.
<3