I was assigned a special slayer task - kill all beasts in slayer mansion. I had not started the task yet, as I was completing a elite TH task, the last section was the rope puzzle in the slayer mansion. I walked in the mansion to get the TH puzzle, and after collecting the treasure chest - I left and it said my slayer task had now been cancelled as I was not up to completing it. I had not even started it, but because I had entered the mansion- It counted as my start. It should at least only start when you kill first monster, not just an entry to the mansion. Will have to wait patiently for another special one day … disappointed in not keeping the slayer task.