Zip does not shrink when one value cannot shrink

[blind-io]

var shrinkable = Arb.From(
    Gen.Choose(0, 10),
    x=> new[]{ x-1 }.Where(x => x >= 0));
var notShrinkable = Arb.From(Gen.Choose(0, 10));
var zipped = shrinkable.Zip(notShrinkable);
zipped.Shrinker((10, 10)); // empty, expected (9, 10)

Actual behaviour:
The behaviour of shrinking using Zip is to shrink each independent variable together and to stop shrinking when one variable stops providing shrink values.

Expected behaviour:
Independent variables are shrunk independently. If one value cannot shrink then the other should be permitted to shrink.

public static Arbitrary<(T1, T2)> Zip<T1, T2>(
    this Arbitrary<T1> first,
    Arbitrary<T2> second) =>
    Arb.From(
        first.Generator.Zip(second.Generator),
        tuple => new[]
        {
            first.Shrinker(tuple.Item1).Select(x => (x, tuple.Item2)),
            second.Shrinker(tuple.Item2).Select(x => (tuple.Item1, x)),
        }.SelectMany());

This implementation provides the expected result.