Unable to Allocate Passive Skills

After completing Trial of the Sekhemas and taking the Witch Hunter Ascendancy, I am unable to allocate the new Skill point I want. To be clear, I am NOT talking about my Ascendancy skill points. Those worked fine. It may have nothing to do with ascending.

When I go into the passive skill tree and try to select a skill I want, it says "Requirements not met." Usually, that means the node is too far away. In this case, I'm getting that message with nodes adjacent to my current nodes. This isn't happening with all the nodes, just a few of them. The one in particular I'm trying to get is the third node down the "Two-Handed Damage" cluster. (From the Mercenary starting point, go down until the paths converge. It's there just on the left. It is shaped like a sword.)