I have two cats I adopted together last year, Smudge and Willow (attaches pics for cute references). Smudge is the shorter-haired, outgoing male and Willow is my timid floof. They rough house a bit and play fight a lot, but sleep on the same bed, groom each other etc. So never really had any concerns about their behaviour. Recently though, Smudge has started hissing if I pick him up and Willow comes into the room? For context, he LOVES being picked up and cuddled to the point where he’ll claw at my leg until I pick him up, but he literally flipped like a switch when Willow walked in - started spitting, hissing and continued as he ran away. Should I be concerned? Or is this relatively normal with dominance, males etc? Any advice is welcome! P.S They’re both indoor-outdoor, eat separately in different rooms and have a litter tray each.