I have found 2 issues with chapter 3 in completing the required objectives.
1) In the fully operational objective, the objective is to build 5 warships. I had to build 6 in order to move on. Not a serious issue, just a bit expensive to field the extra ship.
2) In the winter is coming objective, I need to return all of my units to the mainland. Unfortunately, some of the units I took across the water were defeated and the ai will not capture/execute them. These units are still counted within the total I need to return.