Instead of selecting the filter from the drop-down, select More Filters from the bottom of the list to open the More Filters dialog. Select the Late Tasks filter and click the Edit button. The Late Tasks Filter uses the Status field to indicate whether a task is future, on schedule, or late. The definitions used are:

If the task start date is greater than the status date, then the Status field contains Future Task.

If timephased cumulative percent complete is spread to at least the day before the status date, then the Status field contains On Schedule.

If the timephased cumulative percent complete does not reach midnight on the day before the status date, then the Status field contains Late.

So, my guess is as you have not updated the task its percent complete is not where it should be. It is not based on Finish dates alone.