Project task end date


I use a start/end date and a %complete column to update various tasks in a Smartsheet and I have a question on updating the end date field. If I mark a task at 100% on a given day, why is the end date field not updated to that particular day?

For example, in the above task, if I change % complete to 100% today (4/13/23), why does the end date not update to the current date? The end date will just remain the same at 4/18/23.