Why Does Scapula Protrude on Bench?

Everytime I try to focus on bringing my shoulders back and down on the bench or even a row, I noticed that my scapula protrudes even at lockout. I dont think this is right because especially on the bench, my bench becomes unstable and weird at lockout. I am starting to get confused on this retract the scapula …

Could be an issue with the muscles that attach to the scapula, or with the shape of your rib cage or thoracic spine. See a competent physical therapist if you want it fixed. Can’t be assessed online.