I reported the problem through email and the direct support option but haven't heard anything. The latest FNC Blox 18.104.22.168 does compile for macOS 64 but if freezes when you click an element in the blox control. Also, the lines aren't drawn correctly. It works fine on macOS 32 and Win 32/64.
We are currently busy investigating the issue, we need to update our environment first to be able to compile and test for macOS 64 bit. Stay tuned, we'll followup via email.
Thank you Pieter. I hope they are easy fixes.