I downloaded the current KDE ISO today and installed on an older laptop.
Two issues:
(1) Getting error message on boot which lasts a good 15-20 seconds?(see photo below)
(2) Why is LibreOffice no longer installed on fresh Manjaro installation?
That’s not an error message. It’s the output of an automatic file system check. It says “clean” because there’s no error on your filesystem. You have boot messages disabled, so that message just lingers there until your GUI is loaded. I can’t say why libreoffice is not included, but it’s very easy to install with pacman.