i am trying to click on Fallen_Roses's account but it just sends me to my account page

that's because there is no user with that name. the closest to it is this one, https://subeta.net/users/FallenRose hope that helps!

Did they change their username perhaps?

You're looking for ! :) I guess the cache hadn't updated to show the new username when you were looking, it can take some hours ^^