BUG – Gift on race

I don't know if I'm posting on the right place, but here we go.THE BUG: During a race, if I get a gift 'box', after the race is over, when opening it, the game crashs and I lose what I've got on the race, including the gift. I have an iPhone 5S, iOS Version: 8.4, all updates on AngryBirds GO already done.