Odd level-up bug

I logged on to league this morning, and found that I was level 50, even though I had been 49 when I logged off. I had the capsule in my inventory and was able to open it. After playing one game, I got the level-up notification. I had received 561 xp, which put me at 571 xp past level 50. I didn't get a second capsule.

So it seems I got some extra xp overnight, and different parts of the level-up process responded to it differently.