Omg...that "end" is a mistake right?

Yes. Mangago.me has a bug somewhere in there system (maybe they had a user input something and it set the wrong flag). This often happens with manga chapters. The (end) gets appended to the chapter link for some reason. http://www.mangago.zone/read-manga/yamada_kun_to_7_nin_no_majo/ is an example where this has happened a few times. You can see multiple chapters in a row 193(end) 194(end) and then 195 with no end.