I haven’t directly worked with the de-occluder, but interesting that it’s not snapping back. The old CinemachineCollider (which we didn’t actually cover in this course) offered the option to pull in (zoom in until no collider is occulding the camera) or pull up (my personal preference). Again, it always snaps back where it was before the occlusion occurred.
I like the name change from CinemachineCollider (vague) to CinemachineDeOccluder. The new name says what it does and does what it says. The old name is, as I said, vague.
Looking over the documentation, it looks like the fix here to get it back to where it should be is by adjusting the Damping, lower is faster, higher is slower.
https://docs.unity3d.com/Packages/com.unity.cinemachine@3.0/manual/CinemachineDeoccluder.html
One caveat, however, is that it appears that the DeOccluder doesn’t memorize where it was when you encountered the occlusion… this means that for something like a freelook camera, the return position may not be where it was when you started. It should return to a calculated position based on the positioning component’s calculations. (This was actually true of CM2’s CinemachineCollider as well)