debconf resume_device sets non-existent UUID

Fresh install of 16.04 amd64.

Installed the package and noticed whilst update-initramfs is running that cryptsetup reports two swap devices, one - a UUID - of which doesn't exist on the system. Eventually tracked it down to a UUID in /etc/uswsups.conf but have not been able to figure out where it came from originally.

$ update-initramfs -u
...
cryptsetup: WARNING: found more than one resume device candidate:
                     aaf6753d-aca7-4cbd-9367-50ca48d2f76f
                     cryptswap1
...

$ cat /etc/uswsusp.conf
# /etc/uswsusp.conf(5) -- Configuration file for s2disk/s2both
resume device = /dev/disk/by-uuid/aaf6753d-aca7-4cbd-9367-50ca48d2f76f
compress = y
early writeout = y
image size = 2147483647
RSA key file = /etc/uswsusp.key
shutdown method = platform

$ grep -C2 -rn aaf675 /var/cache/debconf/*
/var/cache/debconf/config.dat-5227-Name: uswsusp/resume_device
/var/cache/debconf/config.dat-5228-Template: uswsusp/resume_device
/var/cache/debconf/config.dat:5229:Value: /dev/disk/by-uuid/aaf6753d-aca7-4cbd-9367-50ca48d2f76f
/var/cache/debconf/config.dat-5230-Owners: uswsusp
/var/cache/debconf/config.dat-5231-Flags: seen

$ cat /proc/swaps
Filename Type Size Used Priority
/dev/dm-5 partition 8701948 0 -1

$ ll /dev/disk/by-uuid/
total 0
drwxr-xr-x 2 root root 240 Apr 29 22:13 ./
drwxr-xr-x 8 root root 160 Apr 29 22:13 ../
lrwxrwxrwx 1 root root 10 Apr 29 22:13 0349c8e6-66e9-4b18-b2d4-03cca09e6968 -> ../../sda2
lrwxrwxrwx 1 root root 10 Apr 29 22:13 1c6eb216-7bfa-4500-b2d2-30b0457d85c1 -> ../../sda4
lrwxrwxrwx 1 root root 10 Apr 29 22:13 1CAC-4496 -> ../../sda1
lrwxrwxrwx 1 root root 10 Apr 29 22:13 50e85da8-68c7-4a55-be02-d8a5a2f9b6d3 -> ../../dm-1
lrwxrwxrwx 1 root root 10 Apr 29 22:13 7f19968f-b571-4a1c-ab18-13a84755eac4 -> ../../dm-5
lrwxrwxrwx 1 root root 10 Apr 29 22:13 92129011-2780-4884-9ff5-523d37fcc3f5 -> ../../dm-2
lrwxrwxrwx 1 root root 10 Apr 29 22:13 a41a60bb-958e-4130-b6eb-d1116bd978b9 -> ../../dm-4
lrwxrwxrwx 1 root root 10 Apr 29 22:13 b4065821-
98f8-4068-a877-b0ab541031b1 -> ../../dm-3
lrwxrwxrwx 1 root root 10 Apr 29 22:13 c5e71a84-d082-4f4b-bf40-edec4936862f -> ../../sda3
lrwxrwxrwx 1 root root 10 Apr 29 22:13 e0e3a6ad-2e6f-4409-b3cb-b0db178ccb28 -> ../../dm-6

$ sudo blkid -s UUID /dev/sda? /dev/mapper/*
/dev/sda1: UUID="1CAC-4496"
/dev/sda2: UUID="0349c8e6-66e9-4b18-b2d4-03cca09e6968"
/dev/sda3: UUID="c5e71a84-d082-4f4b-bf40-edec4936862f"
/dev/sda4: UUID="1c6eb216-7bfa-4500-b2d2-30b0457d85c1"
/dev/mapper/cryptswap1: UUID="7f19968f-b571-4a1c-ab18-13a84755eac4"
/dev/mapper/LUKS_BOOT: UUID="e0e3a6ad-2e6f-4409-b3cb-b0db178ccb28"
/dev/mapper/LUKS_VG02: UUID="0Zt03x-WS8N-dN97-QYKi-wpOV-dBcc-KwkSTb"
/dev/mapper/VG02-home: UUID="a41a60bb-958e-4130-b6eb-d1116bd978b9"
/dev/mapper/VG02-rootfs: UUID="50e85da8-68c7-4a55-be02-d8a5a2f9b6d3"
/dev/mapper/VG02-usr_local: UUID="b4065821-98f8-4068-a877-b0ab541031b1"
/dev/mapper/VG02-var: UUID="92129011-2780-4884-9ff5-523d37fcc3f5"