I haven't received a badge since July 19th. Since then I have answered at least three questions that should have earned me a
nice answer badge, and I haven't been awarded any of them.
I was wondering if anyone was noticing anything similar.
Occasionally, you will not receive a badge because you "lost" a badge, only the system does not take them away. Simply, the next time you would have received that badge, you don't. I wouldn't be surprised if a number of people are experiencing this on SO due to the number of questions migrated to both meta and SU since their launching.
IMO this is very likely due to meta-questions being migrated here, as a lot of the meta-questions were quite popular and probably had badges attached.
You never lose badges -- you just don't get new ones until the count is >= what you're supposed to have.