Was this changed recently?
Up to now you would stay outside of the inner circle and enter at 20/30 to put it back to 30/30 and it would consume one stack, but I did WBR today and each time I entered the middle at 20/30 it was wiping 12-15 even 20 stacks at the same time immediately (all stacks were gone after two minutes), does it also accounts for the boss or the little demons summoned by the assault gimmick that stand inside the circle? Does it count the time you spend in the “in-between” area? Because this makes WBR unplayable at the moment…
[Same problem happens in JSR, sometimes you lose one stack, sometimes you lose (number of partymembers) stacks.]