I got the strange key from xur before I progressed the magnum opus quest and when I reached the point to where I have to give banshee the blueprint there is no dialogue or prompt that gives me the forerunner. I tried a bunch of things and as a last ditch effort I abandoned the quest to hopefully fix it. After I got the quest back from the archive it reset back to the where I have to obtain the strange key from xur. The funny thing is that when I went back to xur there is a check mark next to the key because I already obtained it and used it to open the barrier. I am now soft locked out of the forerunner and can’t get the dope exotic :(