Dont see that transponder on G18, what kind of lnb are you using? Also, don't see that channel listed any where, but I have heard of it before. Sure it's on G18?
Most likely , as the other reply said, its a channel with Dolby Digital audio (AC3), which most fta rec won't play. Most have an audio output, a digital port that can be connected to a home theater or other amp that can decode Dolby sound.