I received the Yearling badge yesterday, which is normal, but then got another one today. Perhaps I am just confused on how this badge works, but it seems like it should wait a year before awarding it a second time.
The badge has a very simple algorithm. As quoted by Jeff Atwood:
You'll get the yearling badge as long as you have at least (Years * 200) rep by the target date.
They don't actually check that the 200 reputation was gained in separate years.
Since your recent answer has gathered a lot of reputation in the last couple of days, and you have more than 3 years time on the site, its retrospectively triggered 2 yearling badges. Infact if you continue to gain reputation, and hit 600 you will gain another yearling badge at that point, but you won't get a 4th until you hit 4 years and 800 reputation.
The fact that this happens for your meta profile too is not surprising, since you don't gain separate meta reputation, that is linked to your main profile.