DBus prefix of data server breaks integration with calendar etc.

After migrating to a more flatpak oriented installation, I was surprised to notice that Gnome Calendar (also flatpak) and Gnome Contacts (flatpak as well) don't see the information provided by the evolution data server anymore. I suspect it might be related to the fact the DBus names are prefixed with "org.gnome.Evolution" meaning the services are now called "org.gnome.Evolution.org.gnome.evolution.dataserver.*". What is the reason for this prefix being introduced in the first place, and would it be possible to get rid of it?