Same issue with an Asus ROG Crosshair VI Hero WiFi (ALC1220) running Mint 19 with the 4.19.3 Kernel from the Ubuntu Mainline PPA.
Playback works, recording cackles with static (this also gets worse if another software is playing something back, i.e. running mumble together with a game), and starting Audacity results in the previously described high pitch bug that needs a reboot to clear.
Same issue with an Asus ROG Crosshair VI Hero WiFi (ALC1220) running Mint 19 with the 4.19.3 Kernel from the Ubuntu Mainline PPA.
Playback works, recording cackles with static (this also gets worse if another software is playing something back, i.e. running mumble together with a game), and starting Audacity results in the previously described high pitch bug that needs a reboot to clear.