As with past limited edition recipes, rather than being forced to make it to level 100 to receive 5-star mastery for the recipe, you only have to make it to level 20. However, once users reach level 20, they've been running into a problem - their mastery sign has only a single star, rather than five.
My mastery sign [pictured] is one that is suffering from the glitch, but rest assured that it is just that - a bug. You don't have to actually reach level 100 to master this recipe (since it has limited time availability, we're thankful for that), and Zynga has acknowledged the issue over on the game's official forums. The issue is reportedly "under investigation" and we imagine Zynga will release a fix for it sooner, rather than later.
Have you reached level 20 of your Green Rose Crafting recipe only to have a glitched Mastery Sign like mine? Let us know in the comments.