Similar as bug 1175045, this happened after upgrading Leap 15.1 to Leap 15.2
using the "zypper dup" method:
GRUB enters rescue mode because of "error: symbol 'grub_file_filters' not
found.".

Once being able to boot (using the "super_gub2_disk_hybrid_2.02s10.iso" rescue
CD this time), using "yast2 bootloader" and just applying the settings
suggested fixed the problem. (Rebuilding the kernel via dracut did not fix the
problem)

I'm afraid the typical user will be quite unhappy if the system stops to
boot...