The Bug:

If you feed a Sniffer while it is digging for seeds and put it in love mode, it will not get up, and instead lay there motionless without sound (unless it takes damage) for a little while, then proceed to dig again but with no animation nor does it respect its "Explored Coordinates" or "Sniffer Diggable Blocks"

I don't believe this duplicates anything as you need to feed it for it to keep digging which takes a seed in Survival, so it's not a true exploit, but it is still very strange behavior, which can be observed clearly in this video:

SnifferExploit.mp4

How to Reproduce:

1. Let a Sniffer search for seeds and start digging. 
2. Once it has begun digging, make it enter love mode by feeding it
3. Note how the Sniffer does not get up, and instead lays there motionless and silent
4. After a while, the Sniffer will dig a second time, but with no animation. You can feed it another seed during this time to keep it laying down and repeat the cycle