This was flagged to the devs shortly after the daily reset, and then it was acknowledged as an issue. However, given the little time before the reset, as I post this, it is unlikely you will get this changed.
It is an annoying challenge as Messi never had more than 5 assists anyway, but if you want to give it a try, simply put Messi as an ST with either two wingers or CAMs behind and run up towards an opponent's goal, then pass it to the running CAM/wingers behind you. Also, make sure that you score own goals (yes, lame but effective) to get extra time.
Main thread: [Bug] Record Of The Day Event Challenge: Assist 6 Goals with Messi | EA Forums - 13038219
This is basic stuff and it’s easy to fix — gift every last user the shards. When you make a mistake you need to own it, and that’s the simplest, most honest, thing EA can do to make things right. It costs them nothing compared to the goodwill it buys. (Which most likely means they’ll do the opposite, lol!)
We both know, but what happens remains to be seen, especially that today's challenge is also bugged :|
