Hey folks. ( spoilers ahead, you have been warned )

So, I wanted to finish the game by siding with the Institute and finally get to the last quest. After destroying the BoS and going back to the Father/Shaun on his death bed.

I speak with him, hear his last words and a cutscene appears, OK seems to be working normally. But for a split second before the cutscene begins, the incombat music begins and stops and when cutscene ends the combat music begins again which btw never ends, I get the Quest Complete, including EXP reward, courses comes to greet me and congratulating me for the victory.

No achievement pops up, I go look up my achivements and see that it says 100% done but still not unlocking.

Is this a bug or am I missing something?

And yes, this is on Xbox One.