Bugs on event

hello i think there is something wrong with the event “better fighting trough science pt.5” during the last mission i had to get the last decoration but i didn't get it, it still shows that i can perform and get that decoration, but it doesn't show any character the mission and everyone who had to perform the event the mission shows that they have to do some task at the beach and get money for it, but there is no such task among the task books and it doesn't end, it always shows and shows. please write me🙏