I’d just like to interject for a moment. What you’re refering to as nonbinary, is in fact, UNG/nonbinary, or as I’ve recently taken to calling it, UNG plus nonbinary. Nonbinary is not an operating gender unto itself, but rather another free component of a fully functioning UNG system made useful by the UNG corelibs, shell utilities and vital system components comprising a full gender as defined by POSIX.
*UNG -> UNG’s Not (a) Gender
This could be a case of nodes running outdated software, the current standard protocols can handle any unknown configuration just fine. These are a source of a lot of holes and vulnerabilities that can pose a serious risk, they should be updated as soon as possible. If you have to keep outdated systems in your network e.g. running on legacy hardware, or make the ocasional connection, you’ll have to monitor them and isolate them from your critical infrastructure, at least with a good firewall and a strict configuration when possible.