Not sure if this has been mentioned yet but I found a rather annoying and amusing bug.
1. cage a pet
2. put said pet in a guild bank tab
3. take the pet out of the bank and move it into your inventory
4. put something stackable (might work with anything, but what I used was flasks/DMF cards) into the exact slot that the pet was in
5. Whatever you put in that slot now looks like it's a pet as long as it's in the bank (stack of flasks will look like a stack of pets).
I have confirmed that it's not my client that's derped up so let's see if someone else can reproduce it!
So if this is actually a working bug I guess don't go buy guild banks filled with millions of gold worth of pets I guess, not that that was very likely! ;P