selects on vrp (= atm_iv - rv_cc_20) exceeding 0.08 and then measures atm_iv's own subsequent change: vrp is not a different quantity from the outcome, it contains it, so an extreme vrp reading is partly an extreme atm_iv reading. An unusually extreme value tends to be followed by a less extreme one purely by chance, so this design finds an apparent effect even in data with no relationship at all. Testing it honestly needs a null that reproduces that tendency, which this harness does not implement. Not tested -- not rejected on evidence.