New power manager or locker error since latest update

[MR ZenWiz]

I run Xubuntu 16.04 LTS.  Up until the last update, I was doing fine,
but now I'm seeing errors like this on a regular, though long-time
delayed, basis:

$ [29757:29782:0203/005937:ERROR:object_proxy.cc(583)] Failed to call
method: org.freedesktop.PowerManagement.Inhibit.Inhibit: object_path=
/org/freedesktop/PowerManagement/Inhibit:
org.freedesktop.DBus.Error.ServiceUnknown: The name
org.freedesktop.PowerManagement was not provided by any .service files
[29757:29782:0203/005937:ERROR:power_save_blocker_x11.cc(334)] No
response to Inhibit() request!
[29757:29782:0203/005938:ERROR:object_proxy.cc(583)] Failed to call
method: org.freedesktop.PowerManagement.Inhibit.UnInhibit:
object_path= /org/freedesktop/PowerManagement/Inhibit:
org.freedesktop.DBus.Error.ServiceUnknown: The name
org.freedesktop.PowerManagement was not provided by any .service files
[29757:29782:0203/005938:ERROR:power_save_blocker_x11.cc(406)] No
response to Uninhibit() request!

I thought it might be a power manager thing, but I have that disabled
from the startup session because it interferes with xscreensaver and
my ability to run sound track while the machine is locked or the
laptop lid is closed.

They seem to show up mainly when I unlock the machine.

I'm seeing this on my desktop and my laptop.

What changed that would cause this?

Thanks.

MR