I have the same problem, tried meditating all times of the day without luck.
I'm also having this same problem, I have the latest patch and am running the hard copy version of the game on PS4. I have saved and reloaded at different distances around the site, and have tried meditating in different areas as well to no avail.
I have been searching for White Gull in the game and found out you can get it from either Kiera Metz or this location once the site is cleared, howeverand now I'm unable to clear this site.I took the option to kill Kiera during the quest
I'm becoming increasingly frustrated as I'm level 23 in the game and refuse to start over due to a bug, and just so I can simply obtain the alchemy ingredient White Gull. I hope that in future patches the bug at this abandoned site will be fixed.