Running a fresh install of the latest stable UT, but finding that the ability to take/make calls fails after some prolonged period after boot. I see messages like this in the syslog:

Aug 19 11:11:06 ubuntu-phablet ofonod[1896]: Activating context: 1
Aug 19 11:11:07 ubuntu-phablet ofonod[1896]: Unexpected data call status 4100
Aug 19 11:11:07 ubuntu-phablet NetworkManager[2389]: <warn> [1629400267.0031] ofono: connection failed: (36) GDBus.Error:org.ofono.Error.Failed: Operation failed
Aug 19 11:11:07 ubuntu-phablet NetworkManager[2389]: <info> [1629400267.0035] device (ril_1): state change: prepare -> failed (reason 'modem-busy') [40 120 23]
Aug 19 11:11:07 ubuntu-phablet NetworkManager[2389]: <info> [1629400267.0056] policy: connection '/xx/context1' failed to autoconnect; 1 tries left
Aug 19 11:11:07 ubuntu-phablet NetworkManager[2389]: <info> [1629400267.0057] policy: disabling autoconnect for connection '/xx/context1'.
Aug 19 11:11:07 ubuntu-phablet NetworkManager[2389]: <info> [1629400267.0057] policy: Disabling autoconnect for connection '/xx/context1'; setting retry of 30.
Aug 19 11:11:07 ubuntu-phablet NetworkManager[2389]: <warn> [1629400267.0071] device (ril_1): Activation: failed for connection '/xx/context1'
Aug 19 11:11:07 ubuntu-phablet NetworkManager[2389]: <info> [1629400267.0104] device (ril_1): state change: failed -> disconnected (reason 'none') [120 30 0]
Aug 19 11:11:07 ubuntu-phablet NetworkManager[2389]: <info> [1629400267.0132] policy: Device 'ril_1' has no connection; scheduling activate_check in 5 seconds.

Is this something that's addressed in the test releases?