We had a degraded performance last night with a duration of 13 minutes around 11 PM. This degraded performance was not caused by the code, platform, or any other fail-point but rather a mis-interpreted DDoS attack. It was not a DDoS attack, however there was a massive swell of donors at a specific minute that caused an alarm to trigger that began throttling connections. It seems that this "false attack alarm" was caused by a combination of last minute media blitzes and email blasts.
While we had our DDoS triggers set at a limit 3x the max traffic seen for almost 24 hours at this point, this spike was 2x that limit. Which caused some connections to not load immediately or with delay. In this case, a page reload (or two) would bring up the donation form.
The issue was resolved in about 10 minutes, and the impact was minimal.