Old topic I know but I have a fix that worked for me with the same problem.

Using an app to force 30fps fixes it completely, in my case I used Nvidia Inspector although I had to delete the Nvidia control panel profiles for the game first. To note, I also tried different vsync settings even ones that should lock to 30fps but they only helped partially.

Note this is for software 3D, I don't know if this will help with the same problem in hardware accelerated mode.

The Grayface patch (2.0) also works due to using hardware acceleration AND having the better textures and palettes from software 3D (best of both worlds) but comes with it's own problems such as no-looping music, FPS drops, and a couple of gameplay changing bugs the gog versions does not have.