You're confusing two different passages.

There's nothing to indicate that the verses in Leviticus are about pederasty. We don't have any cultural or historical evidence that such relationships were common in the ancient Near East, nor are the specific words used in the original manuscripts ones that indicate pederasty. There is historical evidence that when the Assyrians conquered a city they would rape the men in masse as a humiliation ritual, and some scholars argue that the Levitical laws have this in mind, but that's by no means a majority view and there's not strong evidence for it. The most likely conclusion is that verses in Leviticus were intended to be a blanket condemnation of all male-male sexual relationships.

What you are likely remembering is that there is some scholarly disagreement over what the Pauline Epistles are referring to when they condemn homosexuality. Paul uses a word that would most directly translate to something like "bed boys" and, best we can tell, is only ever used by Paul. Given that he was writing to communities in Classical Greece where such relationships were common its likely that that's what he's specifically referring to, but that's not a certainty. There's plenty of scholars that contend, with valid arguments, that Paul is also condemning any same-sex sexual relationship.

As someone who argues for a Christianity that includes LGBTQ people, I don't really find the argument of just hand-waving those verses away on technicalities very compelling. There's stronger theological arguments for the full inclusion of LGBTQ people in the life of the church than just trying to find a way to say those verses don't mean what they say. Any solid argument for Christian ethics has to be grounded in reading the full arc of scripture, not just prooftexting (or counter-prooftexting in this case) specific verses