Unfortunately, I missed some places when fixing the privilege escalation issues for 2.8.1.  Luckily, the entire WordPress community has our backs.  Several folks in the community dug deeper and discovered areas that were overlooked.  With their help, the remaining issues are fixed in 2.8.3.  Since this is a security release, upgrading is highly recommended.  Download 2.8.3, or upgrade automatically from your admin.