This is one of the reasons for bug #1388065. Taking a look at the logs in that bug:
Oct 31 06:13:15 ubuntu-phablet ofonod[1936]: io_disconnect: disconnected from rild
Oct 31 06:13:16 ubuntu-phablet ofonod[1936]: mtk_send_sim_mode: failure sending request
Oct 31 06:13:16 ubuntu-phablet URfkill[9498]: <warning> Could not set Online property in oFono: GDBus.Error:org.ofono.Error.Failed: Operation failed
This is one of the reasons for bug #1388065. Taking a look at the logs in that bug:
Oct 31 06:13:15 ubuntu-phablet ofonod[1936]: io_disconnect: disconnected from rild org.ofono. Error.Failed: Operation failed
Oct 31 06:13:16 ubuntu-phablet ofonod[1936]: mtk_send_sim_mode: failure sending request
Oct 31 06:13:16 ubuntu-phablet URfkill[9498]: <warning> Could not set Online property in oFono: GDBus.Error: