grubenv not updated when new kernel installed

I have a bunch of machines running RHEL7. Normally when yum installs a new kernel, the /boot/grub2/grubenv file is updated to point to the latest kernel. However, on one particular machine, the grubenv file is not updated. Is there a log of what yum does when it installs a new kernel that I could look at? What is the process (script? program?) to update grubenv when the kernel RPM is installed?
Thanks,
Allen