Why is VP Osinbajo sitting far from Buhari & other presidents

Is Prof Osinbajo not Nigeria's Vice President? 

The other day he was lock out of a secret meeting of  Mr President and now he is sitting so far from President Buhari and other African presidents? The Nigerian president is pictured with President of Chad Idriss Deby, President of Niger republic Mahamadou Issoufou and President of Benin Republic, Thomas Boni Yayi at Aso Villa yesterday. Maybe that's where he's supposed to be seated?