Jaheira is by default a druid/sorcerer and thus will benefit from it. .
Why would she be a Druid Sorcerer? She's always been a Fighter Druid.
Because Larian.
Yeah, that's funny, but is this confirmed? I seriously doubt this. She was portrayed with twin scimitars on her back. No Druid/Sorcerer would equip twin Scimitars.
Was it something to do with the spell she cast? Or was it datamined? I was wondering how a druid/sorcerer would work stats-wise. Not exactly an intuitive dual-class pairing.