The content of the text area of my courses disappeared

Hi,

I have a course online right now and I have a text in each lesson, yesterday when I tried to modify a word of a text I didn't find the text in the text area, for editing I can't see the text but if I go to the website as if I were taking the course I can see the text normally, any idea on what's going on?

how can I attach screenshots here ? so you can have a better idea !