Quest Citadel for final fragment is unreachable. Is there anything I can do?

After mapping for 40 hours to collect the crisis fragments for the stronghold fight the last last citadel I discovered is impossible to reach. Will more spawn and is there anything I can do about this? Is the final stronghold fight going to be impossible for me to do now?

https://gyazo.com/e169722770c26cf0ff86cfb8714a4db4