I've seen bows within spec'd brace come apart. It's not uncommon to twist them up an inch or so over factory spec.
Typically one doesn't just twist the darn thing up, rather they shoot it with proper arrows and feel the vibration and hear the noise and twist it to where it suddenly just "behaves". Any more and you start losing performance, there's no gain (except in poundage).
My PSE at factory spec is a piece of crap. It has a lot of shock and if shot there would be tossed in the dumpster.
However, twisted an inch higher it's pretty decent.
Most recurves come apart from poor stringing practices or leaving them in a hot place. The bow that you saw blow apart might have had such a prior stress incident. Do you know its full history?
It might have been braced a little high but that alone is not proof of the failure's cause.
If the gentleman was pulling it hard, beyond the limb working range (into the wall), that'll stress them. Twisted up in brace but not drawn to end of limb working range does what?
Nothing.
I've seen a lot of bows come apart, stringing/hot storage or dry fires are the main culprits. After those it'd be drawing some models hard into the wall.
Brace an inch above spec.........nope.
