[GAMEPLAY] Bug: FPS Freeze upon learning ability LVL 1

When I learn an ability for the first time at level 1, my FPS will drop to 0, and the game will freeze for a 1-3 seconds. Then it will be back, and everything will be normal for the rest of the game. This doesn't happen to me every game, but it happens to me all the time. It may have happened very rarely at other times, but almost always is lvl 1, when learning the first ability.