It certainly looks a mess when you see the departure times from Greystones post-Sept 8th. For example there is a departure at 0752 and 0754 on weekdays. Impossible!
I assume its the usual Irish Rail incompetence. Incidentally if you look at the service announcement for August 26th for the Papal Mass, the Intercity information is quite garbled: some trains to Dublin are mentioned, but not others. What's up? And this is a day on which many people who are not used to using the railway will be left a bit bewildered. Once again Irish Rail incompetence.