Karma boost doesnt work!
I used one today, and it did not work! I got the same ammount of karma with or without boost.
You are not alone..unfortunately it does not work.
Actually they do work, and rather well.
It is not displayed in the popup when you get the gold reward for the event, however if you calculate your karma before and after the event, you’ll see you are getting substantially more.
It’s a display issue only.