Generally speaking, it's a rule of thumb for major updates like KDE 5.22 or Gnome 3.xx to wait for that point release that follows it, which is usually not too far behind. Having the latest packages is always nice, but it's not fun when you gotta deal with bugs that should've been stomped out before release. Sometimes though if the build is stable enough the devs may release the first stable version, but generally the devs do like to wait for that point release to help minimize any bugs/regressions for the users since that'll be much less of a headache approach in the grand scheme of things.