I suspect that the GOPE figured out they could not defeat Trump in the primaries and Manafort was brought forth to Trump as a way to sew up the nomination and to make nice with the GOPE. Hey Donald this guy will help you sew up the convention and the GOPE likes him and can bring a peace and reconciliation between you.
The ultimate plan of the GOPE was for Manafort to sabotage the Trump campaign after the convention assuring they remain in power even with a Hillary presidency. And witness once Trump left the convention through in some cases his own self-inflicted wounds or GOP inflicted wounds the hits kept coming and Manafort
Trump figured out there was a Trojan Horse in his camp and acted accordingly.
That’s a good analysis and I agree completely.