Can you try ACF 5 with WPML 3.1.5 or older ones ?
Also i had problems with them also, on WPML, and after a quick chat they told me author of ACF isnt responding to their mails, dont want to work with wpml bla bla, im 70% shure its not true…
Would love if @elliot can say anything about situation, and me2 also think they want us to use Tools (plus buy Views).. i dont care i did use Tools and Views, but dont want it anymore, i slowly tested ACF and for me it was far greater tool.