Category not showing correctly in plans

We have a category that appears out of order when the plan view is displayed as group by category. We have checked and re-checked the category configuration and cant find a reason for it.

The categories on the project area are in a pretty common hierarchy:

Unassigned (Root)
->Project Area
-->Category 1
-->Category 2
-->Category 3
-->...
-->Category n

There is not any nesting below the main category level. This is the hierarchy we're seeing when we set a view of a plan to group by category:

Category 3
Unassigned (Root)
->Project Area
-->Category 1
-->Category 2
-->...
-->Category n

We haven't been able to figure out why this particular category appears before the category hierarchy when we are in a plan.

The other peculiarity is that when we don't filter by empty categories, we don't see the empty categories in the plan. We know we have some empty categories for some iterations, but they don't show in the plan.

Has anyone seen this before? Any recommendations on things I should look for?

Dennis Hurlbut