I have noticed, however, that the ideology tree does have some glitches.

First, sometimes the selected element of the tree does not remain "filled in" after unlocking it, and it can be unlocked subsequent times (at least, you can spend the points, though I'm not sure if the benefits stack).

Second, sometimes when you open the ideology tree to spend points, a specific element of the tree is highlighted and the "unlock" button is available. If, however, you select a different element (that you have enough points to purchase), the "unlock" button becomes unusable. And when you click back on the originally selected element of the tree, the unlock button remains unavailable.

The only way to correct this that I've found is selecting the element from the tree that you'd like to purchase, then click "done" instead of "unlock" (which isn't available anyway), then navigate to the ideology tree once again--where the element you selected previously is the default highlighted element and the unlock button is once again available (unless you click anything on the tree, including the already selected element).

I didn't have this problem the first two times I played, but I only selected from one tree each of those times. The third time through I completed the available tiers of both the benevolent and pragmatic trees.

That being said, I'm not sure if the glitches are related to having two trees active, or if they are related in some way to the pragmatic tree (since during my first and second games I was malevolent and benevolent respectively). In my next game, I plan to play as pragmatic only.