Thanks, that's a useful demo. I think you just about figured it out with your workaround. Several effects (including replace color) do un-premultiply (divide by alpha), process, then premultiply (multiply by alpha). If the alpha is 0 (transparent space), it does a divide by zero, which is probably undefined behavior. For some reason only iOS handles this differently, but I suppose it is allowed to, since dividing by zero is a weird thing to do.
My fix is slightly different - it just skips the divide if the alpha is zero. I patched several other effects which had the same issue as well.
Thanks for the report, should be fixed in the next build.