Trust was not flawless for me at start of Shadowbringers by any means. I was especially frustrated with Y'shtola, who stood in about half the AoEs.

The AI did improve over the course of the expansion, and I expect the same to happen for Endwalker Trust as the developers collect data on the most commonly seen problems.

The main thing to remember is the AI is pretty limited. The NPCs have their script they stick to for reacting to mechanics. If you pull mobs/bosses out of the expected positions, the NPCs may not react correctly. It pays to adjust to how they're doing things instead of expecting them to adjust to you. Especially important - they do not like big pulls no matter how much some players do. If you force a big pull, expect pain.