Regenerating the initramfs:

https://documentation.suse.com/sles/15-SP5/single-html/SLES-administration/#sec-boot-initrd-regenerate

In that section it says:
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However, there are some occasions when you need to regenerate an initramfs manually:

    Adding drivers because of hardware changes

    Moving system directories to a RAID or LVM

    Adding disks to an LVM group or Btrfs RAID containing the root file system

    Changing kernel variables 
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Please add an additional entry to warn customers of another scenario for which they need to regenerate the initramfs.

* Adding, removing swap devices or recreating swap area

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below that it could be described as:

Adding, removing swap devices or recreating swap area
   Whenever you add or remove a swap device or recreate a swap area with a different UUID, you need to update the initramfs as outlined in Procedure 16.1, “Generate an initramfs”. You may also need to update GRUB_CMDLINE_* variables that reference resume= in /etc/default/grub then regenerate /boot/grub2/grub.cfg as outlined in section 18.2.1.
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