I believe they concluded that Bowyer spun out intentionally to bring out a caution flag. That allowed his teammate to pit under caution, giving him an advantage over other drivers that had already made green-flag pitstops.
No penalty for the spinout. The penalty had to do with pitting on green to change the race order.
If Bowyer spun out intentionally, there needs to be a penalty because he risked his and others’ lives pulling the stunt.
If there is nothing in the rule book about intentionally causing a crash, then he gets a pass this time, but it needs to be in the rule book starting next season.