Right click on the proof of discovery in your item hangar and show info so you can see the full name of the one you have. I am betting it is the wrong proof of discovery. There are three or four different ones.
It’s not a “bug” - the career missions work. If you actually scanned down the data site, warped to it and hacked the can to get the proof of discovery it should work. You can try clearing your cache in case something is stuck there, if that doesn’t work, submit a help ticket asking the GM’s to reset the mission for you.
If you got the proof of discovery by any other means the mission objectives are not complete.