Per the patch notes:
I've only got 3 meadow trails since the event started. Has anyone got one from killing monsters, fishing or gathering yet? Curious on where to get these to drop.
Posted Sep 30, 2017, 7:12 AM UTC
I think they either have a extremely low drop rate (1 in a billion chance) or don't drop at all since Meadows are the items needed to make the Shiny Boxes
I have gotten 3 extra. 1 fishing, 2 grinding mobs.
They're extremely rare. if you're not active grinding, gathering 8+ hours a day you probably won't get the 20 needed for a 2nd shiny box.
I get them through the event and that will give just over 20 of them. Would like more then 1 set of 20.
i am grinding 6~8 hours a day and no meadow yet.
I have been afk fishing 24/7 since the patch launch and i have not had one
I got 1 so far from grinding probably the rate of ogre ring drop.