The cited media states that Robert Moreno is disappointed with Luis Enrique. The Asturian considered the former coach as "disloyal", but Moreno seems to have a different version of the facts.
'TVE' revealed an alleged offer from Enrique to his former second coach. He proposed that he leave his post in the Spanish National Team and enroll with him in a project in the Premier League, although the team in question has not been specified.
Robert rejected the proposal, because his big dream was to lead the Spanish national team in the Euro 2020. The Catalan understood that, in addition, it was something he deserved due to the way his team had been performing.
According to this information, the reasons for the rupture are roughly twofold: Kepa's starting role and Robert Moreno's giving interviews to the media.