Didn't realize someone else already made a post about this. Are you also on Firefox, by chance?
https://itch.io/t/4637664/post-bodies-sometimes-use-nbsp-instead-of-spaces-on-fi...
Viewing post in Problem with   in formatting
I am not. And if a sentence is made up with nbsps, the rendering browser will not break the lines at the nbsps but at any space available or when the line ends in the middle of the word.
If nbsps are created by simply typing, that sounds very annoying. I know they are sometimes created when copy pasting. And I think by typing two spaces. If so, there should be a nbsp between two and spaces when you inspect my post.
And if I recally correcly, if you delete characters and then press space. So there might be one in front of So.