The last time I wrote about Guinea-Bissau (in September 2015), they were on their third prime minister in one month (Pereira was dismissed by President Vaz, then Dja was rejected by the Parliament, then Correia was appointed). All of these characters were members of the same party, the PAIGC, which controls the presidency and the Parliament, but there is conflict between the two branches of government.
Since September 2015, the country has had two more prime ministers. In May 2016, Vaz ejected Correia and tried to bring back Dja, but he was rejected again by Parliament.
ECOWAS intervened to help - the Liberian president, Ellen Johnson Sirleaf, held negotiations with the three main parties in Guinea-Bissau. Following the negotiations, in October Vaz dismissed Dja (which was what the PAIGC in Parliament wanted) and in November appointed Umaro Sissoco (which was not what they wanted). The PAIGC and one of the main opposition parties, União para a Mudança (UM), said that another candidate, Augusto Olivais, had been agreed to in the negotiations.
On December 13, Sissoco selected a cabinet which the PAIGC in Parliament rejected.