I see that on Mojave, disabling FinderSync extension from System Preferences doesn't actually disable the extension in Finder. The supposed-to-be-disabled extension still functions normally. I need to kill the Finder process or the actual FinderSync process to actually disable the extension in Finder. Is everyone else seeing the same behavior? If so, is this a bug or a feature? :) (I vote bug btw :)). On 10.13 and earlier it works the way you'd expect it to -- the extension is indeed immediately disabled in Finder.
Just speculating here, but are we supposed to use the 10.14 specific API showExtensionManagementInterface to do the disabling/enabling in Mojave? (https://developer.apple.com/documentation/findersync/fifindersynccontroller/3021184-showextensionmanagementinterface)
Thanks