Basically, by destroying the crystals too early at a certain part of the script, the script gets confused and breaks.
The Sentinel doesn’t move, while being invincible, and the entire mission is pretty much over.
Unless you have someone that can do knockback and knock the Sentinel off the ledge to reset the script.
It’s extremely annoying when this happens, especially that’s the very end of the level.
Reyna for one can do this with her dome thingy. Haven’t played enough characters to know who else from experience, but I’m guessing Montana should be able to?
Those would be the two that come to mind.
But 95% of the time when the glitch happens, you don’t have them on the team. If you have Montana, the guy may not have picked that helix.
Too many wheels in the script, and if a part breaks the entire fight is lost. Simplicity, sometimes, is the better policy.
What helix does he need?
Maybe i’m wrong but from my experience this has nothing to do with the shard-crystals. As far as i can say ( and the sentinel bug happened two times while i was there ) it happens if someone stands in the way of the Sentinel when he wants to jump back from the plattform to the main area and then he get stucked at the edge of the main area because he can’t land where the script wants him to. The teams i was in allways try to destroy the crystals fast and this never seems to be a problem. BUT maybe i’m wrong.
And no matter what is the cause for the bug, the devs should really take a look into this, because it is soooooo frustrating when it happens.
Best regards.
It’s not about destroying them early:
If you destroy them before he jumps, it’s still OK. But not mid-air.
Ok i replied to the thread opener …
… and didn’t notice the other comment.
Best regards.
My friend did this on Purpose to see it… Advanced Hardcore, over an hour to get there safe and sound and then he needs to see that glitch…
Called it a night after that.
…I mostly use Ambra on that map because she’s such a tank and melts everything so mind blowing fast.
Anyway, I had spec’d for her Push, and tried multiple times, even with Ult events, he wouldn’t budge.
What everybody else said: A most annoying bug 
And these days, I without exception send messages to entire team before the end jump that activates
The Old Sentinel, warning/reminding about the 2 clusters.
Better safe than sorry.
I forgot to take a screen shot, but I did accidentally glitch him in a different location. On the stairs, near the second shard “island”. He went invincibility and just froze. The island came up, but myself and my ally didn’t touch the shard crystals at all.
I think we just did too much damage and scripted his next stage of summoning the swarms at the same time. 
And as a stop-gap:
Put a timer on the invulnerability. 10 seconds should be more than enough.
I’ve seen that happen once before. I spawned a turret while a thrall was over the top of the base. The turret seemed to stick to the thrall for a bit (until I killed it), before finally deciding it just wanted to hover at the top of the rock slope (between the turret and the base in your screen shot above.)
Unreal things happen in this game…
Just…
Always pick Reyna…
Nah. I’ve seen it before in a game you weren’t a part of, Wise. The turret was destroyed by either a Thrall or a Guardian, but it kept floating away…
Oh, I saw this glitch a few days ago. But it’s not gamebreaking, he unfroze when we destroyed those shards.
He did not for us. After a bit of a wait, we broke the shards and he stayed frozen. So we started going through our 12 lives. And he never unfroze.
Pretty much across the board, any map that has enemies “jump onto/into the map” from outside of it, the game has a high chance to break. This happens in the experiment, sentinel, saboteur, algorithm, etc. Can we please just have all mobs spawn and stay on the playable field? I have lost 10+ games due to glitched mobs.
If it’s part of a wave, waiting should result in a time-out which effectively clears the wave and continues the mission (even if there’s still a glitched enemy showing as a red dot on the map.)
The game-breaking glitches I’ve seen all seem to involve bosses of one sort or another (Old Sentinel, the ice golem between Geoff and Isic, etc.)
