Cannot see update to recent linux kernel 5.10.19-1~bpo10+1 (from 5.10.13-1~bpo10+1)

[l0f4r0@tuta.io]

Hi,

I'm running the following kernel:

$ uname -a
Linux  5.10.0-0.bpo.3-amd64 #1 SMP Debian 5.10.13-1~bpo10+1 (2021-02-11) x86_64 GNU/Linux

Backports repository is configured:

$ cat /etc/apt/sources.list
deb http://deb.debian.org/debian/ buster main contrib non-free
deb-src http://deb.debian.org/debian/ buster main contrib non-free

deb http://security.debian.org/debian-security buster/updates main contrib non-free
deb-src http://security.debian.org/debian-security buster/updates main contrib non-free

deb http://deb.debian.org/debian/ buster-updates main contrib non-free
deb-src http://deb.debian.org/debian/ buster-updates main contrib non-free

deb http://deb.debian.org/debian/ buster-backports main contrib non-free
deb-src http://deb.debian.org/debian/ buster-backports main contrib non-free

However, apt doesn't inform me about new version 5.10.19-1~bpo10+1 (according to https://tracker.debian.org/pkg/linux):

$ sudo apt update
[...]                                                                                                                                               
Hit:3 http://deb.debian.org/debian buster-backports InRelease
[...]
Reading package lists... Done                       
Building dependency tree      
Reading state information... Done
All packages are up to date.

apt policy doesn't see any newer version as well:

$ apt policy linux-image-5.10.0-0.bpo.3-amd64
linux-image-5.10.0-0.bpo.3-amd64:
  Installed: 5.10.13-1~bpo10+1
  Candidate: 5.10.13-1~bpo10+1
  Version table:
*** 5.10.13-1~bpo10+1 100
        100 http://deb.debian.org/debian buster-backports/main amd64 Packages
        100 /var/lib/dpkg/status

Could you explain me why I can't update to 5.10.19-1~bpo10+1?
Is something misconfigured somewhere please?
Are mirrors simply not up to date yet (5 days old)?
Thanks in advance :)
Best regards,
l0f4r0