I use the same FB app for both dev/live. I've made sure fb.js is correct. I just pushed quite a lot of code, fyi. I tested a lot, but you never know. I've never seen anything like this and don't know how to fix.
To see, click the links and try to share on facebook: dev http://dev.disheroo.com/GuestMeal/chicken-puffs-broccoli-sliced-apples/105
live https://www.disheroo.com/GuestMeal/chicken-puffs-broccoli-sliced-apples/105