I guess a recent example I can use is Gulpin. I bred a female Gulpin with a male Gengar to teach Gulpin Dream eater, but when it hatched it also had Shadow ball, but this move is not listed under the breeding move set?
Also, I bred female Absol with male Tauros to get Zen headbutt, and when it hatched it had Rest attached but this move is also not listed as a breed move?
I've also noticed the same discrepancy on other online guides, but maybe I'm just missing something ??