I think this is intended behavior. Do note that walking with your dagger onto a monster is
not a body kill but rather a touch kill.
To see the difference: playing as a goblin you can kill monster by stepping on them, we call that body kill. But golems, rock giants, waterskippers or seep are resistant to a body kill due to the fact that they either leave something after their death or are on an inaccessible terrain.
But you can do it all with a dagger, hence you kill them on touch. The reason you end up on the target's tile is because touching happens before the actual movement.
The same analogy works for walking on or off the oremites - you can step on an enemy standing on oremites because the first action which happens is you stabbing them with a dagger and only afterwards you make the movement. When you are trying to attack an enemy from the oremites you can't, because your dagger is still sheathed.
Unless there are further objections I am marking this as not a bug
.
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