if you do /recipe map the crafted map wont appear until you click on the map in the middle of the crafting table and then if you clicked the crafted map it will crash you.

Nice catch, can confirm.

latest spigot 1.9.4 and the latest essentialsx from the dev builds

Which version of essentialsx, spigot, and which version is the client? Like does it happen with a 1.9.2 client on 1.9.4 server but not 1.9.4 on both?

I can speak for 1.9.4 client/server.

and which version of essentialx?

b330

I think this was a client side bug, when I looked into it.

Is there anything we should do about it? If we disable /recipe map then they can't see the recipe, which then sort of becomes a broken feature :P Otherwise I can picture people using this to cause grief to others, so maybe have a yet another configurable feature?

Recipe is currently disabled within Essentials, and also this sounds like a client-side crash (which Essentials would at best be able to mitigate, however players can avoid the issue by simply not intentionally clicking the map).