How many traitors did you kill to get 690 karma?
Also this is not really a bug, sadly a traitor SHOULD know better than to run into the blast radius of a C4, but sometimes it is caused by the malicious intent or stupidity of the c4 placer. Let's say the traitor buddy is trapped in a testing room, is it their fault they died, or yours?
I think it's better that it stay as is.
It happened over a couple of round that i planted c4 in the same place in homegrown and therefore there is no place for them to be stuck. I do not know the total number of traitors killed but i think it was low.
I just think that the karma should be transferred over too say the person who got killed by the c4 or no karma reduction for either party.