I'm not sure if you had any corn in the bag during the "trial run". If there was no corn in the bag and it was microwaved for any lenght of time ... there is a very good chance it would catch fire , just as if you put a match to it. The microwaves would have not had any "bulk" to disperse the wave and would have gotten the fabric/batting to the point of combustion.. just as if you ran the microwave with nothing in it ( which is never recommended).