After booting with break=bottom kernel parameter I can see that symlinks are in fact present at the initramfs stage.
They are gone afterwards post pivot_root & systemd start (the bcache dir isn't even present while it was there)
ubuntu@maas-xenial4:~$ ls /dev/disk/ by-dname by-id by-label by-path by-uuid
After booting with break=bottom kernel parameter I can see that symlinks are in fact present at the initramfs stage.
They are gone afterwards post pivot_root & systemd start (the bcache dir isn't even present while it was there)
ubuntu@ maas-xenial4: ~$ ls /dev/disk/
by-dname by-id by-label by-path by-uuid