Can you give me an example where an object (less dense than liquid) is floating in liquid and buoyancy acting on that object is more than the weight of that object ? It is impossible , isn't it? Because for a floating object buoyant force is always equal to the weight of object.
It depends on what you mean by "floating" and "in liquid".
If it is under the liquid and floating upward against friction and other resistance, then yes, the buoyancy is greater than the weight. If it is under the liquid and tethered by a line, then again, buoyancy is greater.
If it is floating on the surface and has been dropped and is bobbing back to equilibrium then buoyancy is greater.
If there are waves, then the buoyancy oscillates between greater than and less than the weight.
For buoyancy to be equal to weight you have to specify an equilibrium condition, like the usual classical mechanics derivation that starts with "assume a homogeneous and isotropic medium" (made out of the same stuff everywhere and having the same properties in any direction).