On 20190518 (pacific) I got this error after the update. This issue was introduced after 20190504 by probably a maintainer not focusing on the task at hand. I have several pi b+. I have multiple BT devices (identical set for each Pi) The BT device issue is with a Microsoft BT Notebook Mouse 5000 that has been in service since my first Pi. After the update these mice had to be paired with their respective Pi -- which never had to be done after an update. HOWEVER, then, after a reboot, sleep, inacitivity, or BT Off, though the mouse is in the device list; it cannot be reconnected without getting the GDBus Error. This is not happening with the BT keyboard. WORKAROUND is to remove the mouse from the device list, on its respective Pi, then pair the mouse, AGAIN, after each time one of these events happens, with its respective Pi.
So, why have BT?
The other workaround is to revert back to the 20190504 update and avoid any updates until this travesty is fixed. I suppose, if I had one I could use a USB or Wi-Fi Mouse which would prompt, "Why have BT?
It is looking like the maintainer deleted a few lines of code; or ... ?
(edit) Is their some BETTER and less annoying approach that would allow me to regain the use of the BT mouse?