Helium-3 sits flat at 1.1 × 10⁻⁵ across the Galactic disk, independent of metallicity and radius (Bania, Rood and Balser 2002), while stellar yield calculations demand low-mass stars enrich it steadily over ten billion years. The standard fix, thermohaline mixing destroying 3He in its own factories, must cancel production almost exactly: a primordial relic preserved by accident of opposing parameterized processes, with planetary nebula yields still contradicting the balance.
The model inherits the problem through its chemical evolution machinery: smooth gas cycling through well-mixed stellar generations whose yields are calculated, summed, and required to match the record. When the record refuses to move, the machinery must be retrofitted with a destruction term tuned to net zero, which explains the flatness by canceling it.
SCT's registered position is the plain one: cascade termination before one second (P40) makes SCT nucleosynthesis identical to standard BBN (P42), so helium-3 is produced at the standard 3He/H near 1.0 × 10⁻⁵ and carried forward untouched (P29, P30). The framework adds nothing to the disk's chemical evolution and asks nothing of it: the production-versus-destruction balance inside low-mass stars is stellar astrophysics, not cosmology, and its resolution belongs to the mixing physics whatever framework hosts it.
That is the same honest stance the framework takes on lithium-7: shared bookkeeping rather than manufactured advantage. SCT declines to spend a premise on a problem whose live uncertainties are thermohaline parameterizations and planetary nebula yields. One labeled secondary note survives from the deposition picture: inflow of unprocessed baseline gas along the collision-built web (P34) dilutes stellar ejecta and plausibly flattens gradients, but no quantitative SCT model is registered, so the flatness carries no SCT claim at first order.
The BBN anchor is the same one behind deuterium and helium-4 (recids 178, 176): one termination clause, four clean abundances, and nothing tuned.
This resolution is developed in Paper 1, From Chaos to Convergent Foundations.
The shared BBN anchor carries the kill: a primordial 3He inconsistent with the standard network at more than 2σ strains the cascade-termination timeline exactly as helium-4 would. The stellar side carries none: whichever way the mixing debate resolves, SCT's registered position is untouched, which is the point.