You don’t mention which Manjaro edition you are using; thus the importance of providing system information with a Support request; it would have told us that and much more.
As mentioned by @Yochanan in the Update announcement comments, if you’re using GNOME, gnome-shell-extension-caffeine is recommended instead of caffeine-ng.
If you still want caffeine-ng (dropped from the repos back to the AUR), you’ll need to rebuild python-ewmh & python-pulsectl first.
Regards.