My Saiga conversion will set off anything fed into it. My CZ carbine will not, similar to what your rifle did. I suspect the folks at Sig need to step back and take a closer look at the AK platform, perhaps strengthen the hammer spring or something.
Ironically a gentleman at my LGS told me the 556r is the greatest thing since sliced bread and came down on any AR-15 like they were junk, having used them for 30+ years. I wasn't convinced.