I didn’t know xorg was packaged by Manjaro - learned somthing new today.
I use tigervnc in several Manjaro instances I have never seen the issue you describe.
Are you sure you have configured tigervnc correct?
Although I am thinking it is not that hard to configure
So what are your usecase and how have you configured the service?
My preferred method to using SSH portwarding - so the login is not handled by the login manager but SSH - which IMO gives the best result as you don’t have to fiddle with the :0 display, no need to run as root but run as user and you get easy access e.g. using ssh keyfiles.