Gosh, Easy, I'm not really qualified to answer this question because I haven't received my first payout yet and I'm approaching my two-year anniversary.
I did hear from another writer, however, that a very popular and successful hub took a nose-dive in traffic (earnings weren't mentioned).
I doubt that you offended anyone or thing. I think that we simply have to take a mature attitude and realize that activities go in cycles. We have to be patient with technical changes, which occur all the time, everywhere across the internet.
All I can say is keep happy, write from the heart, continue doing what you've been doing, and I'm sure those earnings will go back up, perhaps even surpass your expectation.