Multiple errors in Trial of Chaos

I like to run Trial of Chaos over and over with my level 93 Spark Stormweaver but every 10 runs or so I get a bug where 1 of the 3 bosses stops taking any damage and I eventually die.

On resurrecting outside the instance I then attempt to use a new Ultimatum to open the door and begin a fresh trial, but this does not work and I get the message Instance no longer exists and I have to control+click the waypoint to reset the game.

This has happened so many times I should be level 94 by now and I shudder to think how much currency and soul cores have been lost.

Line 991353: 2025/05/10 20:50:14 286453703 3ef23365 [INFO Client 18016] : Cannot connect to instance. That subarea no longer exists.
Line 991354: 2025/05/10 20:50:18 286457671 3ef23365 [INFO Client 18016] : Cannot connect to instance. That subarea no longer exists.
Line 991356: 2025/05/10 20:50:24 286463703 3ef23365 [INFO Client 18016] : Cannot connect to instance. That subarea no longer exists.
Line 991357: 2025/05/10 20:50:26 286465234 3ef23365 [INFO Client 18016] : Cannot connect to instance. That subarea no longer exists.
Line 991427: 2025/05/10 20:51:07 286506625 3ef23365 [INFO Client 18016] : Cannot connect to instance. That subarea no longer exists.
Line 991685: 2025/05/10 20:52:15 286575156 3ef23365 [INFO Client 20016] : Cannot connect to instance. That subarea no longer exists.
Line 993166: 2025/05/10 22:26:31 292230906 3ef23365 [INFO Client 21576] : Cannot connect to instance. That subarea no longer exists.
Line 1001554: 2025/05/12 08:12:46 413803609 3ef23365 [INFO Client 26744] : Cannot connect to instance. That subarea no longer exists.
Line 1018189: 2025/05/14 15:42:33 613588546 3ef23365 [INFO Client 26228] : Cannot connect to instance. That subarea no longer exists.
Line 1018190: 2025/05/14 15:42:36 613590984 3ef23365 [INFO Client 26228] : Cannot connect to instance. That subarea no longer exists.