I think he learned that lying is a great way to conceal spoilers.
And why not?Also if Luke wasn’t he father, doesn’t that kind of render the reprisal of his “the force is strong in my family” monologue in the second trailer utterly meaningless?
No because Kylo Ren is of the Skywalker lineage. Also unless he says those exact words in one of the sequels the monologue means shitall.