I’m holding the electric igniter for a gas range in this picture and you can see the blowout on the burner tube. This happens fairly often. I believe it is due to the igniter being near the end of its working life and intermittently sending enough resistance to open the safety valve which then let’s in some gas, but if the igniter is not working properly then it will not ignite that gas which will accumulate. Then that cycle is repeated until eventually the igniter is sufficiently hot to ignite the gas which explodes!