This does not happen in space, where there are no buoyant forces.
The magnitude of buoyant force may be appreciated a bit more from the following argument.
Notice that the buoyant force is only a little more than half the weight of the steel sphere.
If the buoyant force is greater than the boat's weight, the boat will float.
This means the amount of displaced water decreases, as does the buoyant force.
The buoyant force equals the weight of the water displaced by the boat.
This net, upward, difference is the buoyant force on the object.
The increased pressure will increase the buoyant force on the ball at the original level.
This is due to the buoyant force on the hot gas.
In air, the buoyant force is usually small enough to ignore.