I've never read anything about this and didn't anticipate this happening, but we sent out our invitations and several came back undeliverable/moved forwarding expired, etc. One came back yesterday --- from June 28 --- saying the person was unknown, wrong address. Another lady called this week to check to see if she was still invited; she had received her STD, but no invitation.
We did get the correct addresses for the first bunch, but when we emailed the last person (a groomsman), he said that was the correct address and he didn't know why it had been returned. I addressed a new envelope and sent it today.
The last lady has been away for the summer and the post office was holding her mail. She won't be home until after the wedding. I had to send a duplicate invite to their vacation home (must be nice).
Long story short: make sure you have extra invitations/envelopes for people who have moved.