Description of problem:
Our test checking for error messages during boot from installation media caught the following error message right at the beginning of the boot process:

error: ../../grub-core/kern/misc.c:503:unrecognized number.

It doesn't seem to affect booting in a negative way, however I'm not sure if it can't cause any adverse effect. Also, even if everything is OK, the error message might be confusing from the UX point of view.

Version-Release number of selected component (if applicable):
grub2-2.02-123.el8 / ppc64le (RHEL-8.7.0-20220524.0)

How reproducible:
100%

Steps to Reproduce:
1. Get a ppc64le machine with virtualization capabilities
2. Install packages necessary for virtualization (libvirt, qemu-kvm, virt-install), start libvirtd
3. Get RHEL-8.7.0-20220524.0 installation ISO (tried with a DVD, but boot.iso should work in the same way).
4. Start installation using libvirt, capturing the output from console in a custom log:

1. virt-install --os-variant rhel8-unknown --arch ppc64le --cdrom /var/lib/libvirt/images/RHEL-8.7.0-20220524.0-ppc64le-dvd1.iso --boot cdrom --name rtttest --memory 2048 --disk size=10 --graphics none 2> /var/tmp/vm-err.log --serial file,path=/var/tmp/vm-out.log
   5. Inspect the console output log.

Actual results:
There's a GRUB error message in the log (error: ../../grub-core/kern/misc.c:503:unrecognized number.)

Expected results:
GRUB produces no error messages, installation environment boots up correctly.

Additional info:
After having inspected several beaker jobs at random, I could only see this error message in a VM.