openhabian: [OH3] motd doesn't show correct update count

Issue information:

My openHAB 3 instance has been running for 22 days straight now so I though I’d check for linux updates. But nothing shows up in motd:

But updates are available:

Also there seems to be some duplicate configuration of sources (openhab / openhab2).

I have not touched anything systemwise. This is a default out-of-the-box installation.

System information:

Pi4, installed with the 1.6.2 image.

cat /etc/os-release and uname -m:

PRETTY_NAME="Raspbian GNU/Linux 10 (buster)"
NAME="Raspbian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"

armv7l