The App formula expression for a column in the spreadsheet is only updated when either the row is first created, or when another column in the spreadsheet for the same row is updated. The App formula expression for a column in the spreadsheet is not updated when a virtual column value changes.
When I checked the change history of the spreadsheet, another column of the same record was updated, but the Update date and Updater did not enter any values.
These columns are created as normal columns, not virtual columns, and the formula is set in Formula in the settings there.