Leather Cuirass Lorica Musculata, I used to think no way but

[Magnus]

I'm starting to think that when not in battle, high ranking officers would have been sans body armour. Wearing elaborate tunica, belts, swords, helms, etc.

No different than many of the depictions of the rank and file (including the centurionate) in tunica, caligae and balteus. If you're not going into battle, or it's not time to impress too much, why wear the extra weight? I hate drawing modern paralells with ancient...but the vast majority of soldiers only want to wear their gear when it's necessary to do so. Otherwise they're quite happy to strut around in their "nice" uniforms, whatever form that takes, but certainly not including armour (kevlar, seggies, etc.)

There is no evidence literary or otherwise that states Roman officers wore some type of faux armour made of a textile or leather when not going to battle. To me it makes more sense to depict their rank and importance with tunica/toga, cloaks and ornate belts/sandals/boots and helms than wearing burdensome armour. Going in regular clothing is simply more comfortable, and easier all around. So while it's feasible that they did make leather musculata, there isn't much point in my mind.

And the statuary can only be trusted so far. It is art, after all...and idealized renditions of it.

That's my story, and I'm sticking to it.