When playing my henchmen game as before, I noticed if several of my units gained new levels at the same time, the levelling screen would start to display weirdness.
I experienced the following:
Often: Incorrect talents would be lit up, even if I did not already have these talents.
Rarely: I could skip earlier talents and go 1 step further up the tree, effectively skipping a talent.
Very rare: I was unable to pick a talent that I had not picked.
I assume the problem is inproper initialization of the screen, especially when several sovereigns and henchmen gain level at the same time (perhaps always?)
I will come back with screenshots when it happens again.