Notes app double-click and black screen issue on fullscreen

Hi Apple community, I've had a very rare problem in my note app, and I don't know how to fix it, it consist on that when I try opening a note regularly I have to double click it to write on it, and I don't like that method of working, also at the time of going in fullscreen the other side of my app turns black, do you have any idea of how to solve this/

[Re-Titled by Moderator]