5 stack, you loose 25% health as they "explode" then start from 0, or 1, again, right? What just happened to me was 5 stacked, I lost 25%, then lost another 25% on the next blocked hit... I though upon 'exploding' it reset?
just tested, it resethttps://www.youtube.com/watch?v=OLSLr0Uugfo