It happens all the time guys, it's perfectly normal. There are ridges on the carboy, yeast falls, yeast SOMETIMES LANDS ON SAID RIDGES, just like snow sometimes lands on windowsills, or dandruff on a nerd's shoulder.
It's nothing to worry about.
Do yourselves a favor and quit hovering over your fermenters looking for something that could go wrong,
especially if you don't know if something is wrong or right.
The yeast knows what they're doing, they've been doing what they do for thousands of years, they're the experts not us. Once we pitch the yeast we're not in charge, they are...Our job is done. Our job is to provide a clean factory for them with all the best materials to work with, but after that they just need to be left alone to do what is in their DNA to do... **** like bunnies, then eat sugar, fart co2 and pee alcohol.(How would you like it is someone was hovering around while you were ****ing like bunnies, peeing and fart, and trying to do your job? )Well except for Laughinggnome you probably would hate it right? Same for the yeast......
They can do just fine without us micromanaging them.
Just pitch your yeast, walk away and like Homercidal said, have a rdwhahb moment instead.