Cannot complete Elemental Evil Campaign

I am in the process of tidying up my campaigns and I am short of an item in Elemental Evil to complete it (I have had this issue for a while).
I have completed three parts of it but I am one promises of power short to complete the "Secrets of Black Earth". I have 4 it needs 5. I have been round all npc and the only quest I can get now is continued force from any of the three npc that offer this. I had completed reclamation rock and went back with the seed to protectors enclave etc. It was only right at the end I realised I was one short. The fact that it is giving me the Continued force suggests to me that it also thinks I have completed all of the quest thread, so how could I be short of the "promises" that are rewarded?

I did stop playing the game for a while after elemental evil came out and I know a lot of tasks were reworked. Anyone have any ideas of what I may be missing or how I can get an extra promises of power? I could buy the campaign but 2000 zen for a not very good boon and a tick in campaign list seems like overkill.

Thanks