Okay, this is not the end of the journey, they're just really a slight problem. (And I think someone in here tried to write and this happened too.)
As a poor person, I only use my phone to write, and when I write I always off my data. I don't think that this is a bug, but it really happened twice now for me! I have 6 chapters that been save but when I turned on my Data, Bang! Gone, just like that. It might be I giving a reason on here but it really happened. Bizzare is, one of the novel library chapters is not been touch, lucky me, I poured all of my time in there just to write it. (I might throw my phone, joke 😐)
I really sorry, I just promise but now my promise been broke one day.