buff bug on friends buliding

Hi!

In the game I got a trick and treats quest.:
produce 2 darknesses and buff at least 2 friends buildings with the darkness.
I did both, however the quest seems only recognises the half of the buffing events.
(I buffed 2 different friends with 1-1 darkness, but the quest shows only 50% on the buffing requirement.)
One thing I can think of:
I moved from my friends island directly to the other friend. And buffed both of them in a short term (without returning to my island)
Now I am provisioning a 3rd darkness and will make a 3rd friend happy also.

We worked out that the quest description is probably misleading, the darkness buffs register if you do 2 on the same person.