Mass Update - Date field won't update

Mass Update - Date field won't update

I am having a problem doing a mass update on a "Date" field. I highlight my leads, click on mass update, choose the field, and enter in the date that I want to update.  Then, when I click 'Save', nothing happens. The box doesn't disappear, and it would look like I still haven't pressed the save button. It's almost like it's just frozen, and won't change no matter how many times I try to click save. Other fields will update, including other date fields.

Any suggestions?