I don't think that's at all what is happening. Presumably Kenpom has evaluated the average performance increase/decrease from their previous school to their new school for transfers, and uses that to predict how the new team will do with the transfers. There's a reason why Forbes is viewed as one of the best at the transfer portal right now, because the average transfer doesn't improve anywhere near as much as the recent Wake guys have.
And as Pilchard said, all of the preseason weighting is gone by midseason, so it genuinely does not matter in terms of what we care about, which is having a good NCAAT resume on Selection Sunday.