iOS5 Addressbook bug?  Doesn't display names...

This happened right after I upgraded to iOS5. Some entries in my SMS list are reflected as coming form phone numbers, as:

xxx-xxx-xxxx

show up as the phone number in the SMS lists. I manually went through and fixed a few of them; but, today after I did a restore from the current image, many of them are represented by phone numbers again.

Turns out, the only way you can get them to show up correctly by name is to prefix this with a "1" like:

1-xxx-xxx-xxxx

but NOT

+1 or anything else. And forget foreign numbers that start with 011.

This is a bug. But before I file a request, can anyone else let me know if you've experienced this or if there is a fix/workaround or am I just not understanding what's wrong here.

Thanks.