Seems that this is happening from november 2019 (more or less) and other emulators like kronos and yabasanshiro inherited this bug as well.
Tested with fresh install, default and custom settings, with yabause, kronos, yabasanshiro standalone versions & retroarch core versions. All the same. I think there's no doubt that the problem is on the yabause code in last quarter of 2019.
As related here:
https://github.com/FCare/Kronos/issues/556
Seems that this is happening from november 2019 (more or less) and other emulators like kronos and yabasanshiro inherited this bug as well.
Tested with fresh install, default and custom settings, with yabause, kronos, yabasanshiro standalone versions & retroarch core versions. All the same. I think there's no doubt that the problem is on the yabause code in last quarter of 2019.