I was so happy when I saw the notification, I thought it was a new chapter... but it wasn't
"Official" means its an official translation, so the text might be different. Same story. But the "other" chapter will be fan-translated
They're done by official groups so they're typically a lot more accurate and just look cleaner overall.
Of course there's lots of fan translations that are are also great quality but not always, it tends to be very varied so people prefer sticking to officials when available.
What is the difference between the other chapter and the 'official' chapter???.The stories they upload are the same. I don't understand. Some manga I read are always like this.