In the Rescue from Fort Neugrad mission, why are my contacts waiting for me inside the fort?

It's solved. It was a bit tough one but I managed to fix it.

It seems the bug happened because I joined the Stormcloaks, finished the Battle for Whiterun quest, then enforced a ceasefire in Season Unending then return to Stormcloak questline after I beat the main quest. Early saves are safe but everything after ceasefire results the same. Anyway the fix is as soon I took the quest I noticed Ralof is walking to the Fort, so I used console command "player.moveto 0002BF9E" to spawn next to him. Then I talked to him got the quest and used "movetoqt CWMission04" command to move the secret entrance before Ralof could make his way to the fort.