Won't switch between two users – Kids' Vocab - MindSnacks Review

This is a great app to boost vocabulary and my 8 and 10 year old enjoy using it. However, we set up 2 user profiles and the game won't switch back and forth between users so my 10-yr old is stuck playing his younger sisters lesson. Please fix this.
Review by ----------wwww on Kids' Vocab - MindSnacks.