selects a day-on-day total_oi increase above 15%, but total_oi is per-contract and accumulates over a contract's life, so an ordinary day's change already exceeds that threshold: measured median day-on-day change in this pattern's own 7-45 DTE band is +20.4%, 75th percentile +75.2%, 95th percentile +333.3%. A +15% move is therefore not a surge, it is below a typical day, and this threshold fires on 56.3% of eligible rows -- 198 of those from a prior day of exactly zero open interest, an artificial infinite percentage change rather than a real spike. Retuning the threshold to describe the data was considered and rejected as fitting the answer rather than testing the hypothesis; its mirror pattern, oi_unwind_precedes_iv_fall, is excluded for the same underlying reason. Not tested -- not rejected on evidence.