MANJARO' is not a valid kernel module directory

Currently running: 5.11.2-1-MANJARO (linux511)
The following kernels are installed in your system:
   * linux419
   * linux510
   * linux511
   * linux54

rename or remove in Directory /etc/mkinitcpio.d/

-rw-r--r-- 1 root root  392 Nov  2 16:12 linux57.preset
-rw-r--r-- 1 root root  392 Nov  1 10:51 linux59.preset

I removed the extra from /etc/mkinitcpio.d/ and then ran mkinitcpio -P and update-grub and both commands completed correctly.

and you are sure you are right on unstable branch ?!
:partying_face:

Yes, I am on unstable branch.