Possible errors in Facebook ad targeting?

I've noticed wild fluctuations in my Facebook ad conversion rates, which is surprising since my ads are highly targeted for BrainiacDating.com. I only target about 10% of the singles on Facebook. The day to day conversion fluctuation can be 200%. It's very spiky and while I have not done any mathematical analysis, it seems like my impression volume, 500k per day should be high enough to smooth out the data.

I see some discussion in the FB developer forums of possible bugs, and am wondering if anyone else has seen this, and what magnitude?

FB forum: read more here.