If someone changes their name legally in the USA, they can immediately apply for a US passport in that new name. If someone with an Irish passport changes their name legally, unless it's to revert to a maiden name in a divorce, they have to wait two years and provide proof that they have been using the new name for those two years before Ireland will re-issue a passport in that new name. So there's a sort of 2-year amorphous "who-are-you-really?" zone there. (Dublin has stated that the original Irish passport would still be valid during such a two-year change-over, if there was one.)
Has anyone encountered this situation, and did it cause them any problems?