I am sorry to hear that you ran into this bug. This is a known issue. You will need to contact Dell to find out if they have a fix.
A workaround is to configure the PXE server to reduce the size of the boot menu that the PXE server delivers. Maybe this is the temporary workaround you are already using.
You may have discovered that the latest version of Intel® Boot Agent posted in the Intel Download Center has a fix, but you cannot use this update for built-in network connections. The utility and files only work on plug-in adapters. Built-in connections require a system BIOS update.