because shim when booted from /efi/boot/boox64.efi tries to lookup defaullt boot binary (uasualy grubx64.efi) and fails to find it, and then triggers /EFI/BOOT/fbx64.efi which then tries to create boot entries and boot them.
whereas ./EFI/redhat/shimx64.efi (which must be the RHEL shim, not ubuntu shim) will load and execute /EFI/redhat/grubx64.efi correctly.
Thus statements like "which maas tries anyway directly" is probably not right either, as maas should inspect boot entries and try to load the correct shim directly.
Note that
10156333884e130 e115c1089c9b15a 02 ./EFI/BOOT/ BOOTX64. EFI e115c1089c9b15a 02 ./EFI/redhat/ shimx64. efi
10156333884e130
behave and boot differently.
because shim when booted from /efi/boot/ boox64. efi tries to lookup defaullt boot binary (uasualy grubx64.efi) and fails to find it, and then triggers /EFI/BOOT/fbx64.efi which then tries to create boot entries and boot them.
whereas ./EFI/redhat/ shimx64. efi (which must be the RHEL shim, not ubuntu shim) will load and execute /EFI/redhat/ grubx64. efi correctly.
Thus statements like "which maas tries anyway directly" is probably not right either, as maas should inspect boot entries and try to load the correct shim directly.