[1.05] Weapon Focus talents randomly disappearing from character sheet.

I've observed this twice now. For no apparent reason, one of my characters' weapon focus talents will just disappear from the character sheet. The Accuracy bonus is still granted, but the character does not actually have the talent. Upon leveling up, the talent is offered for picking, and if I pick it the character then has the Accuracy bonus twice (but only one copy of the talent on the character sheet).

Using the console to remove and add the talent back does not seem to solve the problem. In fact, I've accidentally gotten the bonus twice if I try to remove and add the talent back, just like what happens when I take it (again) upon leveling.

The only way I've found to solve this permanently (so there is a workaround, although it requires the IE mod) is to drop the character to lvl 0 and relevel them up. Only then does the talent go away properly (says "character deactivated weapon focus" in the log when they drop to lvl 0, so the bonus goes away) and then come back when I retake it during leveling.