I've registration limited to a set of school email domains, but have regularly used Super Admin to manually add accounts for parents who don't have email addresses in the school domains.
Today - possibly the first time I've tried it since upgrading to 3.2.1 -that's no longer possible; I get the error "Sorry, that email address is not allowed!" I'm using Network Admin > Users > Add new.
Has the functionality changed here? Don't *think* I've done anything likely to have broken it.