Your arch system (with xfce, kde or lxqt) suddenly takes 20 sec to open firefox etc? - eviltoast
Very slow startup on some apps after update
forum.manjaro.org
The posterity is that its been mentioned in the release announcement. (flagged in unstable a while ago … so technically its been in Testing Announcements, etc too) Every release since 28 days ago.

This is a bug I just experienced on one of my manjaro computers. I was puzzled as fuck because cpu/io usage wasn’t high but it was pretty slow.

Maybe this will help someone.