spam logs with "Error getting appointment uris" errors

Using https://launchpad.net/ubuntu/+source/indicator-datetime/13.10.0+14.04.20140225-0ubuntu1

indicator-datetime keeps logging those errors
"Could not retrieve attachment uris: Not supported"

#0 g_log (log_domain=0x80b99db "Indicator-Datetime",
    log_level=G_LOG_LEVEL_WARNING,
    format=0x80bfba8 "Error getting appointment uris: %s")
    at /build/buildd/glib2.0-2.39.90/./glib/gmessages.c:1067
#1 0x0809c297 in unity::indicator::datetime::PlannerEds::Impl::on_appointment_uris_ready(_GObject*, _GAsyncResult*, void*) ()
#2 0xb7d0dfe5 in g_simple_async_result_complete (
    simple=simple@entry=0x81050a8)
    at /build/buildd/glib2.0-2.39.90/./gio/gsimpleasyncresult.c:763
#3 0xb7d0e087 in complete_in_idle_cb_for_thread (_data=_data@entry=0x8274a38)
    at /build/buildd/glib2.0-2.39.90/./gio/gsimpleasyncresult.c:831
#4 0xb7b8dc10 in g_idle_dispatch (source=source@entry=0xb310cc78,
    callback=0xb7d0e060 <complete_in_idle_cb_for_thread>, user_data=0x8274a38)
    at /build/buildd/glib2.0-2.39.90/./glib/gmain.c:5297
#5 0xb7b910b7 in g_main_dispatch (context=0x80deb78, context@entry=0xb310cc78)
    at /build/buildd/glib2.0-2.39.90/./glib/gmain.c:3066
#6 g_main_context_dispatch (context=context@entry=0x80deb78)
    at /build/buildd/glib2.0-2.39.90/./glib/gmain.c:3641
#7 0xb7b91478 in g_main_context_iterate (context=0x80deb78,
    block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>)
    at /build/buildd/glib2.0-2.39.90/./glib/gmain.c:3712
#8 0xb7b9177b in g_main_loop_run (loop=0x80f28f8)
    at /build/buildd/glib2.0-2.39.90/./glib/gmain.c:3906
#9 0x0807d45a in main ()