ACF is broken on 3.18 and edge due to lua-subprocess update
The recent update to lua-subprocess 4068ee17 "main/lua-subprocess: upgrade to 0.02_git20160421" broke many ACF functions that rely on lua-subprocess. For example, any page that displays service status causes an exception. This applies to Lua 5.2 (and even to Lua 5.3 in my additional testing).