No, it's not that.
I know that it tends to jump out when writing, but this specific one appears when I actually make the post, some of the content is just cut off.
You can't scroll it down, because it's isn't there, it just disappears, leaving one part of my post.
I don't know if it's a new bug or what, but it is really annoying when making long posts.
Never mind, I discovered what was wrong. It seems like I made a mistake in the "commands" [spoil, for example] , which caused things to disappear.
Sorry for inconvenience caused >.>