The harpy battle is a mess. I am playing on normal, at level 3. I had to repeat that battle 5 times. It was not unusual to have two party members under the song's control, and half the time my attacks that connected did not break the harpies concentration(leaving aside the fact that I miss well over half of my %65 or higher attacks to this point). I watch a tactician playthrough, he gets one party member entranced, and the harpies only sing their song once. Don't know if anybody else has this issue.