This should use ‘family’, not IPAddress.Any.
My problem description is a little too vague. For the correct description, see https://bugzilla.xamarin.com/show_bug.cgi?id=6057, which is exactly the problem I'm hitting, and which has the proper fix in the description as well.
This one looks like a dupe of another one you worked earlier.
This should be fixed by PR 2274
*** This bug has been marked as a duplicate of bug 6057 ***