mismatch of installed snaps and refresh snaps

I have the following output from sudo snap info pi-kernel

name: pi-kernel
summary: The Canonical Raspberry PI armhf kernel
publisher: Canonical✓
store-url: https://snapcraft.io/pi-kernel
license: unset
description: |
  The Ubuntu linux-raspi2 kernel package as a snap
type: kernel
snap-id: jeIuP6tfFrvAdic8DMWqHmoaoukAPNbJ
tracking: 18-pi/stable
refresh-date: 7 days ago, at 21:28 UTC
channels:
  22/stable: –
  22/candidate: –
  22/beta: –
  22/edge: 5.4.0-1041.45 2021-07-24 (324) 256MB -
  20/stable: 5.4.0-1041.45 2021-07-24 (324) 256MB -
  20/candidate: 5.4.0-1041.45 2021-07-24 (324) 256MB -
  20/beta: 5.4.0-1041.45 2021-07-21 (324) 256MB -
  20/edge: 5.4.0-1041.45 2021-07-21 (324) 256MB -
  18-pi4/stable: –
  18-pi4/candidate: 5.3.0-1015.17~18.04.2 2020-06-01 (77) 190MB -
  18-pi4/beta: 5.3.0-1015.17~18.04.2 2020-01-15 (77) 190MB -
  18-pi4/edge: 5.3.0-1015.17~18.04.2 2020-01-15 (77) 190MB -
  18-pi3/stable: 4.15.0-1092.98 2021-07-26 (328) 184MB -
  18-pi3/candidate: 4.15.0-1092.98 2021-07-26 (328) 184MB -
  18-pi3/beta: 4.15.0-1092.98 2021-07-21 (328) 184MB -
  18-pi3/edge: 4.15.0-1092.98 2021-07-21 (328) 184MB -
  18-pi/stable: 5.3.0-1040.42 2021-06-24 (278) 201MB -
  18-pi/candidate: 5.3.0-1042.44 2021-07-26 (325) 201MB -
  18-pi/beta: 5.3.0-1042.44 2021-07-21 (325) 201MB -
  18-pi/edge: 5.3.0-1042.44 2021-07-21 (325) 201MB -
installed: 5.3.0-1040.42 (278) 201MB kernel

as you can see, the installed version matches 18-pi/stable.

However; when I run snap refresh --list I get the following

Name Version Rev Publisher Notes
pi-kernel 5.3.0-1042.44 325 canonical✓ kernel

why is refresh thinking it needs an update when the version is correct for the channel it's tracking? The listed vale is for 18-pi/candidate, 18-pi/beta and 18-pi/edge