i have a big problem: preston dont give me new mission.

i have finish Humane Error and sided whit covenant.

i try to completed a Minutemen mision in covenant: build defences, kill gunners, when i return to the mayor Jacob Orden he say "remeber what ive say about mr dan" but... i already killed him in Human Error -.- , i have no other option so quest is bloked.....but then another settelment is under attack so i fast thravel there and when i kill the last of the enemy the Minutemen quest upate as if i had succesfuly speack whit the mayor, i return to preston and i completed the mission....but he dont give me any more missions.

i know that everything relate to Covenat is extremely bugged, but i didnt want to kill all those pepole, there is a way out? can someone help me make this bug more visible to bethedsda? is a serious one.

thanks for any help.