The only thing I can think of is something is shorted in the MPEM. My 96GTI will work with any lanyard because we had to replace the MPEM, we purchased an new MPEM and not knowing any better back then never had the lanyard programmed for the new MPEM, but I've never heard of a DESS ski starting without the lanyard attached to the post.
Rather than replace the MPEM I think I would just install a hidden kill switch.
Lou