It has been a while now, and I believe I brought it up in the archived forum (now defunct). On every machine we have installed Manjaro Xfce on, we disable it as part of the normal install. Hidden=false is also changed to Hidden=true. Never had any problems with xfsettingsd.
This workaround was first introduced in the package manjaro-xfce-gtk3-settings (initial commit was this one).
Apparently it had to do with some bug in the theming of xfce4-session-logout dialog window of Xfce. The bug report and philm’s posts on it can be found here: https://bugzilla.xfce.org/show_bug.cgi?id=15712
The bug was fixed, so i guess this workaround is not needed any more.