
Unfortunately for several players, an insidious bug is illegitimately ending honour mode runs right before Act 3’s final boss fight against the Netherbrain. As reported most recently by SlytherJean, there’s a bug with an unknown cause that seems to occur as the player triggers the cutscene at the end of the High Hall sequence before one climbs the stem to face the Netherbrain.
An Unfortunate End
After the short cutscene ends, the player immediately experiences a total party kill (TPK) and is prompted to either delete the save or continue the run in custom mode. This bug has been reported multiple times, including by Reggie_Is_God over a month ago, with them saying “78 hours, nearly a year. And it ends to a bug. Struggling not to throw up at the moment.”

Regardless of the cause, losing hours of time investment is assuredly a sickening feeling. If your run-ending TPK is legitimate, then you’ll feel bitter but understanding, but a bug being one’s undoing is tragic.
Larian Studios has yet to comment on this specific bug, but hopefully, the studio is aware of the problem and can rectify it in Baldur’s Gate 3’s eighth and final patch. There’s nothing to be done for those who have already lost their runs, but perhaps this problem can be prevented in the future.