The new boss health bars do not correctly show invulnerability

I am farming Uber Uber Elder and it's extremely noticeable all the time: often the health bar doesn't switch to show invulnerability I don't think it has shown the Shaper invulnerable ever and sometimes it doesn't switch off when you can actually damage the boss despite it shows invulnerable. But it's not just this fight, I see it all the time, even in acts.