Seabed lower levels box bug?

[root]

I'm not even sure if it's supposed to be this way, but these 4 boxes in the seabed always drop nothing. I thought it was just coincidence but I have broken these same 4 boxes 20+ times now. Is it a bug? Or did they actually never drop anything? The boxes in question are 1 room from the starting entrance in this layout (I circled the map entrance in red).

 

[Aleron Ives]

Those are random boxes, so they can drop nothing or potentially drop something. It's probably just bad luck, assuming other blue boxes drop stuff sometimes.