My connection is always full green bars and fine etcetera. This is the one and only place I have ever been teleported into death pits, and it is SPECIFICALLY when the sentinel awakens. I noticed that when trying to board the platform with the crystals his hitbox was much bigger than when he started recharging (note the strange repulsion when jumping toward the crystals before he was settled).
You can’t jump over to those platforms. They’re kinda there & kinda not there, and totally bugged either way. The boss battle is scripted so they appear, he jumps over and uses them to regenerate, then jumps off and knocks the platform away. If you’re on the platform when he jumps off, you die pretty much instantly, even before he technically kicks it away. But then, he also occasionally jumps back to the dead air where the platform used to be & can just stand there in mid-air. I guess the way the engine works, the platform collision exists in the gameworld, but the game tosses you over & insta-kills you if you’re there outside of the few seconds when they first appear. If you can’t destroy the crystals w/ ranged, you’re pretty much screwed & just need to fight him w/ the extra health. Ambra doesn’t have the DPS anymore to burst them down anyway, using her melee would help a little, but its not enough - she’s kind of a nightmare to play in PvE since the damage nerf.