So, from my reading and forum suggestions, I will blow out my propane lines/plumbing and adjust the ignitor/flame sensor today. Maybe I ought to tweak the ignitor and flame sensor close to the burner as well. What I have learned is that these explosions can be caused by excess propane build up or a lean gas mixture (clog in line, low pressure). Also I have read that a dirty burner can cause this, but I have already cleaned it out and when it did light the entire burner was lit evenly. If anyone else has any knowledge of furnaces please let me know other potential areas to investigate.