Andrew, I may have figured out a run-around for this issue. Added the DHCP/DMZone ip address as a Static IP on the Pix Outside Interface. It has been 4 days since making this change and haven't experienced the issue. Keeping the fingers crossed. Than...
Andrew, I'm having the similar problem with UVerse and Cisco PIX setup. Please let me know if you found a resolution to this issue. As it's very frustrating. Thanks