Indeed, since you only start counting the strangeness when the second one comes up the same as the first one, your chances of seeing the totally perplexing 3 in a row would be 1 in 4 for a character with a random sorcery pick. Really, 25%
Here's how it works: you build a bunch of leaders with random Sorcery picks, and they give you various stuff. Blood, Astral, whatever. Sooner or later, two in a row are going to give the same thing. When that happens, you say "that's odd". Here's where
The Gambler's Fallacy. kicks in: You've already noticed that things are weird, because you got two bloods in a row. Or two Deaths, or whatever. At this point, you are looking at the next character, who is an independent event. So when she comes up, she has a brand new chance of having the same type of magic that the other two got - and if she does you'll flip out.
So as soon as you start counting, you have a 25% chance of getting a "strange coincidence". Now, if you go back in time to the beginning, your chances are .25^3 - 1.6%. But you didn't, you started counting after the second hag had already come up a double.
-Frank