Nothing unusual, cannabis mutations are quite common and it does not affect anything.
It is not caused by anything you did and is a bit like growing a wart or a few zits.
If you are keen, take a look at my diary "cannabis conundrums" and in week 7 I have posted a few pictures of various mutations, including buds growing on leaves, buds growing on leaf stems and even leaves growing out of other leaves. Once you grow for a while, you will soon see how common various mutations appear on cannabis plants.
Hope this helps, Organoman.