I tried a fresh install with today's cauldron.  Everything went fine, and I tried to reboot into the new system.

I had installed the new bootloader on the root partition, and chained to it from my existing cauldron GRUB bootloader (I always install a new system bootloader to its own root partition, and then install it to /dev/sda when I'm ready to make the new system the default).

The boot of the new system shows the old GRUB menu, I select the chain entry for the new partition, I see the GRUB graphic screen for the newly-installed partition, select the "Boot Mageia 3" default, and get a character-based screen from GRUB that prints the kernel line, the root filesystem line, the initrd line, and then freezes.  It's either locked or looping, since it does not respond to CTRL-ALT-DELETE, or to the magic keys.  It looks like a problem with the initrd

The only deviation from my normal install procedure was that XFdrake comes up during install and says that the machine has two graphic adapters, and gives 4 options.  Normally, I pick one of the two, but this time I accepted the default of configuring both.

I'll redo the install selecting one or the other and see if it makes a difference.  But the default choice shouldn't result in an unbootable system.