Exactly, it's not a bug. The backdoor has been functioning perfectly for decades. : 3Intel's statement on the matter specifically says that the exploits are not caused by a "bug" or a "flaw" that is unique to Intel products. Intel also noted that the exploits can "gather sensitive data from computing devices that are operating as designed."
This new firmware disables branch prediction on AMD family 17h processor to mitigate a attack on the branch predictor that could lead to information disclosure from e.g. kernel memory (bsc#1068032 CVE-2017-5715).