I wouldn't even bother to try to fix them - virtually every block has them. You could possibly make things worse, by attempting to repair - it has actually relieved a little bit of stress there, plus, because of where it is, it doesn't affect anything. The only thing I've found, is that since it can allow water to get in the bottom of the stud hole, that stud or bolt can be VERY hard to get out...my studs broke both sides, and they were the only ones that broke - the rest came out fairly easily.

I wouldn't worry about it. I know it goes against our nature, but it's ok...really it is....

R