Win32 bug when SDL_DOUBLEBUF|SDL_FULLSCREEN?

I have an Win32 app which is using the July 16 snapshot of SDL;
it allocates the video surface with SDL_DOUBLEBUF|SDL_FULLSCREEN.
Everything displays fine for the most part, but every now and then,
the display tears for a second. Anyone else seen this?
BTW, also happens with SDL 1.1.3.
– Mike