I've done 80 of those quests already and still no shiny lolFriend of mine got salty when I said I randomly completed an Evolve 3 Natu/Sunkern quest and got a shiny Pineco, while he's efficiently competing 3 quests in one time and got zero after 20+ lol
This event has sucked for me. I got one shiny Houndour the first day and that was it.