Fairly sure that
@AndWeDon'tCare has some insider knowledge on how these events transpired from within the club. I believe he inferred that when the news first broke, and said he understood the reasons for DCE leaving, at least until he went on 100% Footy. If there was any disrespect from inside the club, DCE certainly matched it when he went on that show.
I think (?) both DCE and Mestrov have said they would be willing to have him back in a coaching role post-retirement, so I don't imagine it's anything significant, where relationships are untenable with management, like Des. Could even be a matter on the level of Molo at the Dragons, where someone said he's done nothing since 2011, and he took offence, or something.