With previous versions, on each startup there was an error message "xfce4-settings-helper: Another instance is already running. Leaving..." With today's git version, there is a similar message for xfsettingsd. The reason seems to be that with the default configuration, xfsettingsd is really started twice: Once because it is automatically registered in the autostart directory, and once more because it is in the saved last session. Disabling xfsettingsd in autostart makes the error message go away. Perhaps items which are in autostart should be removed from the saved session or vice versa?
What is the problem exactly?
Except for the message, there is no noticeable problem in the current git version. There was a problem with xfwm initialization in 4.8 release (5639) which could be related to the double xfce4-settings-helper startup, but that's definitely gone now (at least for me). If you are sure that the double start doesn't cause any problems, there is no need to change anything. Is it recommended to disable xfsettingsd in session autostart to avoid the double startup, or should it be left on?
Autostart is a backup if the session failed (due to saving without a running instance for example). We previously had some code to disable autostart when it was launched from the session, not very smart imho. So I can remove the message or make it a bit nicer, but if the message is shown; it's a good thing, because without xfsettingsd not much is working.