I sorta think it's a jealousy issue. Your situation sounds somewhat like what I deal with Schatzie about.
If I hold Annabelle Schatzie absolutely freaks out or if I bath Annabelle. Once Annabelle is from my arms and 4 paws back on the ground Schatzie pounces her. Of course Annabelle ignores Schatzie's bad behavior which amazes me.
If I was Annabelle and Schatzie treated me like she does Id nip her in the butt just to say "back off you little brat"...
