Fire affecting blocks it's not supposed to

I went to create a fireplace in my home like I've done in the past; surround a netherrack block with brick blocks, no wood touching it although my home is made of all wood.
A fire caught in the ceiling of my home AND any adjacent brick blocks as well (if I'm not mistaken they don't catch fire, I've made a fireplace in 1.6.2. with no issues).
I'm hoping this is a bug and not some new block properties in the new snapshots.