Game Mechanics: Tiny Jade Inlaid Coffin (stackable)

[Gaxx]

I just noticed today that Tiny Jade Inlaid Coffins are now stackable. The coffin icon for the item shows a number in the bottom right-hand corner like all stackable items.

Upon noticing this, I stacked 2 coffins together. After zoning I only have 1 coffin left. The second one poofed.

What is the intended functionality of this? I believe they were stackable on live but I am not sure at what point they became stackable (Velious?).

Was something changed last night that caused this?