Liverpool to Norwich service to be spilt up

[hstudent]

I've noticed in the new National Rail timetable that from September the Liverpool to Norwich service will become a Liverpool to Sheffield service and a Chesterfield to Norwich service, with the exception of some evening trains which will run between Liverpool and Nottingham and Sunday trains, which will continue to run between Liverpool and Norwich. Does anyone know if this is a permanent spilt? (It would seem strange if it was a temporary spilt due to engineering works as most are carried out at night and on Sundays.)