What is the difference between MC in a SIP wall and any other cable installed in an insulated wall? Shooting foam in an exterior wall is pretty common and some kind of insulation is pretty much required by law. For that matter a buried cable is also very much thermally insulated.
I think this is just an inspector who is confused by something new. I saw a similar case with a Y-tong concrete structure. The Fire Marshall had never seen it before and refused to believe the state engineer's documents on the plan. It took about 3 months of substantiation from the NRTL, the manufacturer and the engineer to get the CO.
