SOLVED

In regards to the Mastery Cave:

My partner has reached level 10 in all skills and is able to enter the mastery cave; read the letter and the podium but isn't able to select any of the skills. I was able to select two different mastery skills already (I picked foraging and combat if that matters.) They are saying every single one is greyed out even after returning to the cave to check multiple days in a row.

Has anyone else come across this issue? Please let me know if there is a fix for this! Thanks.

From comments: “I believe you need to hit level 10 in all skills and then also earn another 10,000 experience before you can select a specialization. This is how it’s been worked in my multiplayer world, at least. Was totally unproductive for a whole 3 days while I ran around the valley doing nothing but chop trees and collect salmon berries to hit level 10 foraging. Finally did it, and much to my chagrin I wasn’t able to select a specialization until I earned another 10,000 xp.” - @houhghigh