While holding a carrot in the main-hand, you can not place blocks or torches with off-hand. It works with any other food.

Steps to reproduce:

1. make sure you aren't hungry aka hunger-bar is full
2. hold carrot in main hand
3. hold torches in off-hand
4. try to place torches
5. it won't work

Holding any other food, even golden carrots, works, this bug just happens with Carrots as far as i know.

Fix it, mojang.