Blood spot in a castle is eventually gone when you refresh the map,so does that means that there wont be any defense penalty when standing on it? It`s just plain castle hex anyway(although it was suppose to have the blood spot there)
And the rubble only gives a penalty of -10 def instead of
-10 def and -10 atk,that`s what it seems to be.
Any confirmation for both of this?

I checked to see what is was in one of my games, and the bloody remains gave -10 to attack, no defense change.
The rubble gave -10 to defense, no attack change.

Both the rubble and the bloody remains took 5 turns to disappear.

This was NOT in a castle, so I'm not sure what difference the castle slab may make, but that is what it was in regular rough.

In castles the servants are very fast at cleaning bloodspots up thats why they disappear so fast I guess its a bug but it has been like that for long now.