Software bug / mangled input. https://www.sandiegouniontribune.com/sdut-july-4-fireworks-fiasco-solved-technically-2012jul12-htmlstory.html https://www.sandieg

Software bug / mangled input. https://www.sandiegouniontribune.com/sdut-july-4-fireworks-fiasco-solved-technically-2012jul12-htmlstory.html https://www.sandiegouniontribune.com/sdut-july-4-fireworks-f... "The company's statement included an explanation of how fireworks shows are produced through code, with a primary launch file and a secondary back-up. The two files are merged to create a new launch file, and sent to each of the five fireworks locations. Somehow, an "unintentional procedural step" happened in that process, causing an "anomaly" that doubled the primary firing sequence, the report said."