Not sure if hack, bug, or other

Hi,

Overnight tonight – logged out at 12 PST, and logged back in at 00 PST.
All inventory on a single floor (3rd of 6) was changed to stone or charcoal. like right down to the slot/row order.
with the exception of the room my toon was in.

All building material is metal…

15 doors leading from the 8th floor to the 3rd floor were gone as was one wall, on the 6th floor.

The odd thing is, there was no way for anyone to get to that place where the wall that went missing was without being able to fly…

There are no foreign building objects outside or anything.

This is a public server, but because of all of the hackers here I am not going to advertise which.

BUT WTF was this?