Updates to libre office 6.0.3 packages just appeared on my Arch Linux. So I unchecked all libreoffice packages and lo-kde-integration package. When I clicked the "Update selected" button, all unchecked packages were re-checked without any warning and updated together all other already checked packages. It's not the first time that it happens.
I forgot to say that my LO packages were installed from Arch repositories.
Should be fixed as of this commit: https://cgit.kde.org/discover.git/commit/?h=Plasma/5.12&id=be9c3a3363d4d159c2a67ffa442afd07ca0332f1