Can A Key Pass a Bad Code to Another Key?

Yesterday I threw an old Murano key on top of a new one. (The new one
was reprogrammed when I lost a key last summer. I had just found the
"lost" key whose code was no longer valid.) The "new" key was working
all along...up to this AM. When I went to start the vehicle, it
wouldn't start as if it had picked up the code from the "lost" key! I
am down to one key now. I think it would be a huge coincidence if the good key just happened to fail by itself at this time.
My question is this: Is it possible that one key's code could be
altered by being in proximity with another (bad) key?? Does Nissan have
a bulletin on this?
Thanks!
Frank