I'm experiencing the same issue on an F9 x86_64 updated system.  I booted with the rescue disk and everything GRUB-related looks fine.  I ran a memory test which also checked out.  I don't know what component to file a bug against, although my suspicion is that it's anaconda.  Any help would be appreciated.  The system stops at the word "GRUB" and allows no further input.

--
Joel