My question: Which is wrong? The documentation for setting up a software bridge? OR /etc/sysconfig/network-scripts/ifup-eth?
I've a number of functioning software bridges, none of which are in promiscuous mode.
Looking at /usr/share/doc/initscripts-8.45.30/sysconfig.txt, there used to be PROMISC=yes|no option but its now marked as "No longer supported"
Perhaps newer bridge code no longer needs it and your documentation is now out of date?
Kal