That bump, nick or scratch may have happened weeks, months or even a year ago. The nick or scratch can be microscopic in size. Even microscopic manufacturing flaws can be the culprit. I don't see a window behind the stove top but if there is one and the hot sun is beating through it onto nicked or scratched tempered glass it could result in the same outcome.
Richard & Jill
2014 Flagstaff 832IKBS Classic Super Lite
2018 Silverado 1500 Crew Cab Z71 4WD All Star Edition
Camping since 1989, Seasonal since 2000.
Car Shredder Op/Tech, Scrap Metal Recycling - retired