I mean sometimes he did because I've listened to him since I was a baby. I only started realizing when the notes would clash when I was in my early adolescence though. Sometimes he would mix in key unconsciously while sometimes he wouldn't. Most of the times he wouldn't it would be during sections of songs that didn't have a whole lot of melodic content and were more percussive in nature. That way there wasn't a whole lot of note clashing. Occasionally though I would hear note clashes and it would bug the hell out of me but hey he's the old-timer DJ right?

He comes back from the era of Vinyl. He's really good but just doesn't know wtf he's doing from a theoretical perspective cause he never studied theory or anything lol. He just does what he does best!