This isn't bug. You won't receive rewards for activating Jonin medal unless you buy it.
Purpose of giving "trial version" of Jonin medal is to let players test it and maybe they will be interested enough to buy. But you won't get all of the benefits if you have the free version.
For the first time reward for activating the Jonin Medal, is the naruto nine tails permanent or does it change? Mine says the event's deadline is 4 days so does the first time reward change after the 4 days?