This is the third week in a row that I have not been able to spawn a UM boss on the last day of the event. I have tried playing 12 stam dragon road, 15 stam mission 9 and 14 stam mission 8. I am not going to use a stam potion if I cant get 1 UM to spawn out of 4 attempts. It is ridiculous that on day 1 you can spawn on a 3 stam dragon road but on last day you cant spawn for 9 hours... Please fix whatever is causing this.