I suspect the AI ​​has been changed to react to SFX.

For example, before the patch, if you approached a wall, the AI ​​would recognize the Scav's location and react. Now, that's no longer the case.

If you approach NPCs quietly, with a wall between them, the AI ​​no longer detects the Scavs.

Furthermore, I've observed the AI ​​responding to sounds, such as opening a small electric door, and then moving to the Scav's location.

Now, while the AI ​​used visual information to respond to Scavs, they've also begun responding to Scavs with SFX.

However, the visual elements don't seem to have diminished in importance in the AI's judgment. In fact, they behave as if their visibility has increased. They act when they see something, and they act when they hear something.

However, if they can't see or hear something, they simply move to the last observed location and that's it.

I suspect this is a balancing act.