https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1777258 On fresh install on Yoga920 of Bionic Beaver 18, wifi and bluetooth work. Then they degrade with BT not working within a day or five, and wifi is consistently inconsistent. On the bluetooth gui, user is unable to turn bt on or off and the CLI shows no blocking on bt but it doesn't work. I think this has to do with the Qualcomm QCA6174 [168c:003e] (rev 32) on Ubuntu Bionic and the ath10k_pci driver but Qualcomm nor Lenovo have answers.
Updated to 4.18.0-041800rc1-generic and the problem persists.