Same on Windows and HTML5. I suspect it’s the same on every platform. I was able to fix this by increasing the Z position on both sprites by 1.
I don’t know why this is happening though. Maybe an issue with the new render script? But DEFAULT_FAR is -1, which suggests this should work fine with the default far plane.
Since we now also render models by default stencil tests are enabled and sprites should be put on less than the near and far value (ie -1 and 1 are exclusive now).