In GirlPa EN Server, Sayo Hikawa's name is not Saya in the event Backstage Pass. And in the area conversation of Lisa and Tomoe, Lisa Imai's name is not Saya. So, they should have fixed their names from Saya to Sayo in Backstage Pass, and from Saya to Lisa in the area conversation of Lisa and Tomoe, which means this is a name bug (glitch).