Why isn't an animation flipped horizontally when I call setFlipped(true)?

This seems to be a bug, and there doesn't seem to be a way to work around, short of using two sprite sets - one for all the sprites without flipping, and the other set for when the sprites are flipped.

What makes it worse - this means you can't use the animation code if you want flipping, and instead need to implement your own logic, to use the appropriate set of sprites, animations etc.

EDIT: It seems to be fixed in 3.16