Hello would it be possible for you to show mystics AS damage in the damage log?
I'll take a look but I don't think so, at least not in a conventional way. AS is registered as damage over time (in the same way as bleeding, burning and other DoT effects) and I think that there's no information about who dealt the damage available to the client in this case. Think about it like this -- if two players stack bleeding effect on the target, which one should be registered as the damage dealer in target's damage log?
The most we can show is "xxxx damage taken from yyyyy", where yyyyy would be the name of the effect (Absorb soul in this case) but I'm not sure even this is possible.