Summary
In sui-framework/sources/bls12381.move, the doc/natspac comment for scalar_div references a non-existent parameter a
/// Returns e2/e1, fails if a is zero.
public fun scalar_div(e1: &Element<Scalar>, e2: &Element<Scalar>): Element<Scalar>
The parameter a doesn't exist. The other division functions (g1_div, g2_div, gt_div) correctly use "fails if scalar is zero."
Recommendation
Fix the typo, change below code
/// Returns e2/e1, fails if a is zero.
to
/// Returns e2/e1, fails if e1 is zero.