If you really wanted to find out what happened, perhaps you could have talked to CloudFlare to find out how things like this happen. I'm going to guess it's improper programming. Especially when a coding change by GAW seems to fix the issue. However, I'm not positive because I haven't spoken to CloudFlare to get their side or reviewed any of their best practices material (if they have it).
This ^. GAW have blamed others numerous times in the past, everybody from DHL to Rackspace was at fault except GAW itself. This was ridiculous back in May and it still is.