First of all, forgive me if this is not eqemu's matter, but I've seen this happening in various servers and thought it may belong to this forum. Since I haven't been able to talk to admins, I don't know if this has been solved already in up-to-date databases.
The following Shadow Knight spells have the id of the spell that lands when it procs gone by +1:
-
Decrepit Skin (id 8484) should proc
Decrepit Skin Parry (id 8485), but procs
Arcane Aria (id 8486).
-
Umbral Skin (id 15214) should proc
Umbral Skin Effect (id 15217), but procs
Umbral Skin Effect (id 15218).
-
Umbral Skin Rk. II (id 15215) should proc
Umbral Skin Effect (id 15218), but procs
Umbral Skin Effect (id 15219).
-
Umbral Skin Rk. III (id 15216) should proc
Umbral Skin Effect (id 15219), but procs
Assiduous Impurity (id 15220).
According to
this post on allakhazam, this bug may have been on live too, but it looks like it's been fixed already.
Regards.