In the MCD FAQ it says

"You will need to complete the Obsidian Pinnacle mission on Default difficulty before you can play missions from Jungle Awakens. While looking at the Mission Select map in the camp, you can access the Island Realms to start Jungle Awakens."

This is incorrect as in update 1.5.0.0, the requirement was changed from needing the obsidian pinalce to be completed to just squid coast. I think a possible fix is just to simply remove the first sentence.

I've uploaded the a screenshot of the related text. I was unable to find the change on the official change log, but it has been noted on the wiki. https://minecraft.gamepedia.com/Minecraft_Dungeons:Locations

I believe this wiki to be correct and accurate becuase I personally completed some of the DLC levels before I managed to finally complete the Obsidian Pinnacle