I recently needed up update my Amazon EC2 Security Group to allow HTTP and HTTPS. This is a trivial task considering the fantastic tools they give you to easily do this. However to my dismay, every time I tried to add a new rule to the default security group, it would act like it was adding the rule but did not. I tried adding a new security group and rules with the same result. After several trial and error attempts I decided to post a topic on the EC2 forum. Several members were very helpful in their attempt to diagnose the issue but to no avail.
Shortly after posting one of the Amazonians, Luke answered my question. Apparently there was an issue with the US-EAST-1 and EU-WEST-1 regions of EC2. I was surprised that I was the only one to notice this but they fixed it promptly.
The Forum post link is attached.