Where?
Drop boxes that didn't have 24/7 video coverage are a violation of one of the basic principles of holding a valid election, i.e. that the votes always be in the custody of a responsible person or persons from the time they are collected to the time they are counted.
My own belief is that even 24/7 video coverage of a remote drop box shouldn't count as continuous custody, however even the low bar of video coverage wasn't maintained.
All votes dropped into unmonitored drop boxes are suspect and should be challengeable.