Question No sound unless power cycle

Apr 6, 2019
Hello all.
I have an HP Spectre x360 13 laptop that I recently installed Ubuntu 18.04 onto alongside Windows 10. Everything worked fine for the first few days. Switching from Windows to Ubuntu and vice versa took 30 to 45 seconds, and I was pleased with it.
But today, I had been using Windows for a while to do some school work while playing music on Spotify, then I closed it and put it in hibernation for a few hours. After I returned, I rebooted into Ubuntu to mess around with it some more. I opened the music player, but there was no sound at all. I rebooted into Windows and there was no sound there, either. I did a full power cycle (unplug power, shut down completely, turn back on) and booted into Windows and there was sound again. Rebooted into Ubuntu, no sound. Full power cycle again, boot into Ubuntu, there was sound, and so on.
Any ideas on what is causing this?

Edit: On the first power cycle, there was a screen saying something about the CMOS being broken somehow--I didn't catch what it said other than something wrong about the CMOS. After that booted into Windows, the clock was wrong, so I fixed it. Every other power cycle the clock is fine, so I don't know if that's an issue.
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