Pentaho Spoon displays many errors like this in console:
(SWT:12688): GLib-GObject-WARNING **: /build/glib2.0-7IO_Yw/glib2.0-2.48.1/./gobject/gclosure.c:724: unable to remove uninstalled invalidation notifier: 0x7f1f2a537bc0 (0x7f1f6d5af530)
The only adverse effect of these errors seems to be somewhat slower performance.
Ubuntu 16.04, Gnome, Pentaho 6.1 Community Edition.