I’ve heard singers who sound like they’re squeezing their throats like a bagpipe...is that sort of what you mean? That can’t be healthy.
You need air to sing and the most air is in the rib cage i.e. the lungs as you probably already know. Not keeping everything opened up wrecks the whole works in the long run. I think they’ve been singing too much before this finale and it happens. With singing, trying too hard can be unhealthy imho.