- Edited
pacman has no say over when the mirror you use syncs with the main mirror, that is why the tool mirror-check is build into octopi. Updating a system on a (partial) unsynced is just not an option in a rolling distro.
Some mirrors are set to run a cron job hourly, others 4-6 times a day, KaOS has no control over that.
Petty SysInfo tool is showing issues, probably due to not supported language/characters.
But yes, full pacman.log might help figuring why linux-next was added.
And add the output of pacman -Qm
(DKMS message in octopi...)