Inconsistent Boss Invulnerability Indication for Uber Elder

I've just recorded an Uber Uber Elder fight and noticed that the invulnerability shield covering the bosses life bars was very inconsistent and often incorrect.


The Shaper is down to 75%, he's invulnerable and has his purple shield on. But his life bar at the top does not show it.


First portal phase. The Shaper's life bar is still not showing invulnerability.


Second portal phase. Both bosses are invulnerable. But this time the Elder's life bar is not showing it.


After the last portal phase. The Shaper is not invulnerable. In fact, he's about to die. But his life bar shows otherwise.

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