Blue..yeah, disturbing for sure. As mentioned, one possibility is HPOP leak listed here
6.0 PowerStroke bulletins You need to find out if tec. checked for hpop leak? It should be covered under p/t warr. Good luck!
btw..A classic play on words "If no
DTC found/set = could be "SOL until code shows"? Meantime..tsb says code may NOT be set. Definitely classic play on words.."Find another dealer/tech." JMO!