ya as said above, this bug appears when 2 moves have the same word, in this case, "wish"
just let it learns healing wish first, then wish would appear
klefki and rotom learn defog by tutor
but there is no defog tutor in game
tm teacher is a substitute of tm, not a tutor
that's why klefki and rotom can't learn defog from tm teacher
so there is no bug about it