Using 15.0.35
Added a expression column to the album view
As soon as I click on another album in the navigation pane, the expression column drops from the view.
I save the view including the expression as a preset.
Any time you do, the suggested name is MyPreset and no warning that you are about to overwrite an existing preset
Again when navigating the expression drops from the view
Selecting explicitly MyPreset as a view cures this but the expression is displayed as the last column regardless of its position.
You can move it to the front but after navigating is appears as the last column again.