Unexpected behavior of `NonEmptyList.reduce` for tuples of lists

NonEmptyList.reduce used the wrong, or at least unexpected Semigroup instance for tuples of lists. I'm not sure if it's due to cats itself or the compiler though.

Let's say I want to semigroup combine a couple of tuples of lists

Tuple(List(1, 2)).combine(Tuple(List(5)))

I would get Tuple(List(1, 2, 5)), which is expected.

However if I do

NonEmptyList.of(Tuple(List(1, 2)), Tuple(List(5))).reduce

I would get Tuple(<function>). Looks like my tuples of lists not as tuples of List were inferred as tuples of (Int => Int) which is surprising. I would expect the same Semigroup instance would be used in both examples.

I even got

NonEmptyList.of((List(1, 2), List(1, 2), List(5, 6)), (List(4), List(5), List(7))).reduce

to produce Tuple(List(1, 2, 4),List(1, 2, 5),<function1>) on my local machine using scala-cli on Scala 3.7.4 but I couldn't reproduce elsewhere.

Weirder still, this workaround that looks like it would do nothing

def reduce[T: Semigroup](xs: NonEmptyList[T]) =
  xs.reduce

reduce(Tuple(List(1, 2)).combine(Tuple(List(5))))

produces Tuple(List(1, 2, 5)).

Start by reproducing the NonEmptyList.reduce examples with Scala 3.7.4 and compare them with direct tuple combine calls. Inspect the NonEmptyList.reduce entry point and the inferred Semigroup instances for tuple components. Done means the behavior is explained and the reported inconsistency is fixed or documented with regression coverage.