How can Couatl and audio fail twice then work perfectly all in one session without a reboot or reinstall or anything?
The answer is obvious: since Couatl is always the same, it's clear that Couatl itself has NOT failed, but it's your audio driver that has CAUSED the problem, most likely because it might have a bug in the OpenAL support in its driver.
A thing to note: I just rebuilt a new PC from scratch, with Windows 10 freshly installed. Using the Windows 10 audio drivers that came with the mainboard ( ASUS, with Realtek audio chipset ), NORMAL WINDOWS AUDIO randomly disappeared. I'm not referring to GSX or FSX. I'm referring to the normal, standard, sounds that Windows makes.
Searching online, it seems Realtek is blaming Microsoft, and Microsoft is blaming Realtek...
However, when I uninstalled the audio drivers that came with the mainboard, and replaced them with the generic ones that comes with Windows for the Realtek chipset, all my problems with audio disappeared.
I'm not suggesting this might be the same thing that affects Couatl, but it's something you might want to try.