giant crops

So I was doing the Qi Crop quest as per my usual business, when one day, a giant Qi crop spawned! I was not aware that this existed until now, and was wondering if I had discovered it. I did a little digging and apparently ConcernedApe teased it in a tweet, so I'm posting here to wonder if I'm...

SO i am trying to get giant crops...yes I know they take ages and the probability is low BUT I was just wondering if they can occur overnight in the last day of a season?? THANKS IN ADVANCE