Progress keeps disappearing – K-POP Starpic Review

I have had this app for a while now. It’s fun to color the different idols. But, there’s only one problem. I’ve been coloring one picture for a long time. And I was almost done with it. But when I just went back into the app to finish, the picture was blank, like I didn’t even start to color it. I don’t know if it’s a glitch that’s been happening to other people, but could the developers look into it? Thank you!! :)
Review by the potato pear on K-POP Starpic.