I also ran into an interface bug at this point, which might be what ShabyBelle’s bumped into as well:
[spoiler]I emptied the grave, and it said “There’s something sticking out of the wall”, so I DIGged WEST and unearthed the box, which fell into the grave. But I’d taken one too many turns to do it, so GET BOX at that point resulted in me drowning, so I needed to exit the grave first, then re-empty it.
When I re-entered the grave, I was told “There’s something sticking out of the wall”. But this time DIG WEST told me I didn’t want to disturb the remains of the baby.
It took most of a frustrating hour of EMPTYing, DIGging, LOOKing, etc, all to no avail, before I tried a hunch and said GET BOX. (Bear in mind there was no mention of the box in any description of the grave, and it still insisted there was something sticking out of the wall.) That worked. Turned out that when the box fell in the grave, it was definitely there… but there was no way of determining that from any description subsequent to the initial unearthing.[/spoiler]
I ran into a few other places in the game where a description failed to reflect deviations from the initial state of a room or object, but none that caused me trouble the way this one did.