I was able to fix this bug by following the advice of @KAT3561 with a hat tip to @Fruit.Rolls_OLT for some additional advice...
How I got bugged...
a) I'm on Xbox
b) I reactivated the SHD network while in a friend's world....causing my story progress bug (that friend is not bugged FYI)
c) when in my own world, my priority mission was "reactivate SHD network" but when I went to the terminal in the basement there was no interact button
I have a friend who was leisurely working his way through the campaign (lvl 12) and had not completed Federal Bunker yet. So we squaded up in HIS world and ran Federal Bunker in Story mode. After completing it he was NOT prompted to reactivate the SHD network and we realized that he hadn't completed Space Administration HQ either. We then ran Space Admin HQ after which he WAS prompted to reactivate the SHD network in the White House basement. I followed him down there and stood beside him while he watched the cutscene in its entirety. After the cutscene finished we both got the "Mission Complete" notification. I then left his world and loaded into my own. I am no longer being prompted to reactivate the SHD network. FIXED!!
SUMMARY: If you are experiencing this bug, you will need to be in someone else's world when they complete their White House upgrades and reactivate the SHD network. If they have played the story missions in order this will happen after the Federal Emergency Bunker mission. Then you must stay in that world instance until they have completed watching the cutscene that follows the SHD network reactivation.
Congrats to @KAT3561 and the community for finding and sharing this fix. And SHAME on Ubisoft for not providing a hotfix for a game-breaking bug that they've been aware of since before release date. Booooooo!
My buddy is currently stuck due to this bug...
It is an absolute JOKE how Ubisoft/Massive have responded to this GAME BREAKING bug.
I don't get it... The FIX documented does not work as everyone currently matchmaking this mission all have the BUG.
When will this be addressed? It's amazing the customer and bug support has continued from Division 1... total joke.