Why am I only allowed to play on fullscreen with 2 of my characters?

I can't use 2 of my characters unless I am in fullscreen. If I try to select one of them at the character select screen I go back to the login in screen. If I change it to fullscreen and connect with one of those characters and it goes back to borderless fullscreen (because I use 2 monitors and do more than just Path of Exile) then I can't go in an portals or use waypoints. What is going on? Everything I looked up about this shows no solution besides having to keep having to swap to fullscreen.