When configurable columns are added to/removed from the list view, Actions column is always placed as the last column to the right, which ensures that actions offered in the kebab menu are always in the same place and easily accessible.
This behavior is enforced with the fact that Actions column is the only column which doesn't offer the option to be moved using drag and drop.

However, if the process variables are added to the list of configurable columns and are enabled, they are placed to the right of Actions column, which causes Actions column to be moved towards the center of the list view and hence break the above-mentioned behavior and user experience tied with it.