She could have warped the head from getting it hot and it's just got a
compresion leak out the gasket.
( pretty common happening for a hot running aluminum engine )
She just lucked out and didn't blow the gasket near a water jacket.

If you think it's an exhaust maifold leak, blow some soapy water by the
manifold to head mating surfaces when the engine is cold .

Start it up.
You'll see it blowing bubbles if that's the leaking area.

Pfft, pfft, pfft.