Mysticism : help with Stone Form



I'm having a big trouble with the Mysticism spell Stone Form. When people use the spell, and I think this happens when they are equipped with items CastSpeed and WeaponSpeed, their CastSpeed and WeaponSpeed are decreased permanently ... and this is cumulative.

I've disabled the spell while waiting for a fix ... but I should admit I'm not sure what goes wrong.

Moreover, I seem not to be able to fix the "corrupted" players (lol I know this sounds weird).

Here is the part of the code I think that is causing the problem :

                object[] objs =
                    AosAttribute.CastSpeed, -2,
                    AosAttribute.WeaponSpeed, -10
                new EnhancementTimer(this.Caster, 27, "Stone Form", objs).Start();

Thank you for your help,