I have finished The Sea Bound Soul and have all commendations for it, but I did not get an achievement. It's currently sitting at 75% complete. https://imgur.com/gallery/g5VHXZ6
No achievement for finishing The Seabound Soul
How long ago?
try logging out and in?
you on xbox? maybe you can try logging in on the cloud to see if it pops (could try this on pc too if you have access to cloud gaming)If nothing happens in the next few days you can try a support ticket and see how that goes.
I would just run the tall tale again at some point to see if it pops it if nothing else works.
2 / 3