When expanding or collapsing a TreeItem in a TreeView, an incorrect cell index is updated. Specifically, a cell index mirrored vertically around the center of the visible area is updated instead of the correct cell. This indicates a flaw in the cell index update logic or the visible cell list update mechanism.

This issue is particularly noticeable when cells are styled using CSS, as the incorrect update results in a visual glitch or flicker. Even without CSS, the problem manifests as a subtle graphical irregularity due to the rapid update process.

To Reproduce:
- run the attached SCCE
- expand and collapse the item "three"
- observe the item "two" flickering with what appears to be hover state specified via CSS

Clip:

https://github.com/openjdk/jfx/pull/1644#:~:text=Mein.-,Video,-.mp4

NOTE: please check if the issue is observable with TreeTableView as well.