en_tn/lev/20/12.md

lies with

This is a euphemism. Alternate translation: "has sexual relations with" (See: rc://en/ta/man/jit/figs-euphemism)

They have committed perversion

Here God calls a man having sex with his son's wife a "perversion", a serious sin. See how you translated "perversion" in Leviticus 18:23.

Their blood is upon them

The word "blood" here is a metonym for the guilt of putting someone to a violent death. See how you translated similar words in Leviticus 19:9. Alternate translation: "the guilt for their violent death is theirs alone" (See: rc://en/ta/man/jit/figs-metonymy)