+1
This issue was present in WinUAE 2.3.2 too. It's the reason why I don't use vsync.
P.S. To avoid tearing you may use Direct3D + Triple buffering + disabled vsync instead. No tearing, no sound distortion. Not sure about lag, but seems fine to me.
P.S.2. Another solution is to choose PortAudio driver but then I have to raise sound buffer in order to get clear sound.
EDIT. Looks like vsync don't work properly with sound drivers other than portaudio (at least not on WinXP), because framerate locks on 51-53 fps instead 50.