I too found this bug with Ubuntu 18.04 LTS on Nvidia Jetson TX2 system.
Running ffplay :
ffplay /dev/video0
produces:
dbus[9467]: arguments to dbus_message_new_method_call() were incorrect,
assertion "path != NULL" failed in file ../../../dbus/dbus-message.c line 1362.
This is normally a bug
Public bug reported:
An unresolvable problem occurred while calculating the upgrade.
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubuntu-release-upgrader-core 1:16.04.26
ProcVersionSignature: Ubuntu 4.15.0-43.46~16.04.1-generic 4.15.18
Uname: Linux 4.15.0-43-generic x86_64