I've seen this bizarrely happen on a newly partitioned and custom installed Linux install, particularly if you did not properly unmount before rebooting.
You can find reports of it happening on various
How to fix the error: invalid arch-independent ELF magic.
You need to boot into Live/Rescue mode, chroot into your OS properly and then do a grub-install on each drive that nee........
md127 issue, it should be /dev/md3 per mdadm.conf
Any time something is mounted as md127 it almost always means there is no entry for this mdadm array in the mdadm.conf in initramfs (which is separate from your actual /etc/mdadm.conf).
cat /etc/mdadm.conf
ARRAY /dev/md3 metadata=1.2 UUID=b6722845:381cc94e:7a2c5b5f:8e3b7c4f
The reason for this is something strange, most Linux OS's bizarrely always keep their own copy of /etc/mdadm.con........