I migrated a V6.313 backup onto &.260 (all works fine now). Then restored the migrated configuration. It appeared to work fine and started the Configuration Setup Wizard. Since this was a test setup I changed both the internal and external interface addresses which appeared to work correctly but when the box was reset it was still using the migrated values.
I've seen this happen before, but only with one of the earliest 7.x versions... it didn't happen all the time, either... it went away at some point, I guess it's back!