The rings - because they're so large - have to duplicate in the shader work normally done by your graphics card's z-buffer, or else they appear like the first picture. In Oolite 1.79 the way that the camera is set up has changed, and because the shader does so much odd stuff, that affects it - you can see in the second picture the shader trying to hide the bits of the rings you can't see, but it hiding the wrong bits because the camera isn't where the shader thinks it is.