Yes, I've seen this when the outlets are backstabbed.
The HO kept telling me "it can't be a problem with this
socket, cause it works....." and took some Jedi Knight
powers to get that outlet taken apart.
If you need a visual, plug four extension cords, one into
the next, in the form of a mule train. One into the other.
Remove plug 3 from cord socket 2. And then ask the
customer why sockets 3 and 4 don't work. Every time
he tries to plug plug 3 into cord 2, tell him not to.
Look! (plugs tester into cord 2) this can't be the problem
because the socket #2 still works!
Christopher A. Young
Learn more about Jesus
If you have a dead outlet after a good outlet,
it could be a bad connection at the good outlet.